JP7783032B2 - Blended yarn and woven/knitted fabrics - Google Patents

Description

The present invention relates to a blended yarn that has excellent stretch, wet opacity and fastness, as well as ease of passing through manufacturing processes, and to a woven or knitted fabric that has a cotton-like, soft texture.

Conventionally, a well-known and commonly used technique for imparting opacity, UV protection, heat insulation, etc. to woven and knitted fabrics is to incorporate ceramics, particularly titanium oxide, into the fibers that make up the fabric. However, simply increasing the titanium oxide content increases the amount of titanium oxide present on the yarn surface, causing significant wear on yarn guides, rollers, reeds, knitting needles, etc. in spinning, drawing, blending, twisting, weaving, and knitting processes, resulting in the need for frequent part replacement. It also frequently causes fuzzing and thread breakage in the fibers themselves. Therefore, the titanium oxide content has been limited to 2-3% by weight of the fiber constituent material.

To address these shortcomings, sheath-core composite fibers have been proposed (see Patent Document 1). This method involves incorporating a high concentration of titanium oxide into the inner layer and a low titanium oxide content in the outer layer, thereby improving wear on yarn guides and achieving a certain level of transparency prevention. However, this method does not take into consideration the transparency prevention effect after blending, or the durability of woven and knitted fabrics when titanium oxide is incorporated at a high concentration.

In addition, a core-sheath composite fiber has been proposed in which a modified cross-section yarn is added to the above-mentioned core-sheath composite fiber to impart transparency resistance, a dry feel, and drape (see Patent Document 2). However, even with this method, no consideration was given to the transparency resistance effect after blending, or the fastness of the woven or knitted fabric.

Meanwhile, there is a growing need for opacity resistance, with demand for not only dry opacity but also wet opacity. When wet, light scattering is suppressed, making the material more transparent, so there is an ever-increasing demand for highly opaque materials. In light of this situation, JIS L1923, "Method for evaluating the opacity resistance of textile products," was revised in 2017 to include wet opacity resistance.

With regard to wet-state opacity, it has been proposed that hollow multifilament yarns, which incorporate a hollow cross section into a core-sheath composite fiber, are effective (see Patent Document 3). However, while this method takes into account the opacity prevention effect and processability after blending, it is insufficient in terms of wet-state opacity, as it merely measures the decrease in whiteness in a wet state using a unique method.

Fibers that maintain high transparency even after blending have also been proposed, using sheath-core polyester flat cross-section fibers (see Patent Document 4). However, even with this method, there is no mention of transparency-blocking performance in a wet state, and sufficient effectiveness cannot be expected.

Furthermore, the above-mentioned prior art documents (Patent Documents 1 to 4) do not take into consideration the stretchability of the clothing, making it impossible to achieve both high transparency resistance and stretchability, even in wet conditions.

In recent years, in order to achieve both stretchability and transparency resistance, a mixed-fiber twisted yarn has been proposed that combines hollow cross-section yarn and side-by-side conjugated polyester multifilament (see Patent Document 5). However, with this method, the highly transparency-resistant hollow yarn and the less transparency-resistant side-by-side conjugated polyester multifilament are randomly arranged within the fiber bundle, and sufficient transparency resistance cannot be achieved as light passes only through the less transparency-resistant parts, and transparency resistance in a wet state has not been evaluated.

As such, among the blended yarns widely used in general clothing, no material has been obtained that has excellent opacity resistance in a wet state and also has stretchability.

Japanese Unexamined Patent Publication No. 55-158331 Japanese Patent Application Publication No. 10-317230 JP 2016-113715 A JP 2013-44055 A Japanese Patent Application Laid-Open No. 2020-147865

The present invention aims to solve the above-mentioned problems by providing a blended yarn that has excellent wet-state opacity and fastness, as well as excellent manufacturing processability, and a highly stretchable woven or knitted fabric made from the blended yarn that has a cotton-like, soft feel.

The present invention, which aims to solve the above problems, is characterized by any one of the following configurations.
(1) A mixed yarn comprising a core yarn and a sheath yarn, wherein the core yarn is a side-by-side or eccentric core-sheath composite fiber, and the sheath yarn has an outermost layer portion having a titanium oxide content of 0 to 2% by mass and an inner layer portion having a titanium oxide content of 5 to 60% by mass, wherein the titanium oxide in the inner layer portion is of the rutile type, and the mixed yarn covers the composite fiber.
(2) A mixed yarn according to (1), in which the number of loop fluffs of 0.6 mm or more is present in the surface layer of the mixed yarn at a rate of 10 to 300 pieces/m.
(3) A mixed yarn according to (1) or (2), having a stretch elongation rate of 20 to 150% after tensioning at 0.5 cN/dtex.
(4) A mixed yarn according to any one of (1) to (3), having an innermost layer portion with a titanium oxide content of 5 to 60% by mass and a titanium oxide content of 0 to 2% by mass.
(5) A woven or knitted fabric using the blended yarn according to any one of (1) to (4).
(6) A woven or knitted fabric according to (5) above, which has a water absorption rate of within 5 seconds and a residual moisture content of 30% or less after 60 minutes.
(7) A woven or knitted fabric according to (5) or (6), in which the dry and wet state transparency based on JIS L1923:2017 “Method for evaluating the transparency of textile products” Method A (visual method) is grade 4 or higher.

The present invention provides a blended yarn that has excellent fastness and manufacturing processability, and is also stretchable and opaque in a wet state, despite containing a high concentration of titanium oxide in the inner layer, and a highly woven knitted fabric with a cotton-like, soft texture.

The blended yarn of the present invention is a blended yarn consisting of at least a core yarn and a sheath yarn. It is important that the sheath yarn has an inner layer with a high titanium oxide content and an outermost layer with a low titanium oxide content. Having an outermost layer with a titanium oxide content of 0 to 2% by mass reduces thread path abrasion between titanium oxide and guides during the spinning, blending, and weaving processes, enabling industrially stable production. Furthermore, a low titanium oxide content in the outermost layer increases the reflectivity of the fiber surface. The high specular reflectance, particularly in a wet state, creates a mirror effect, making it difficult to see the back side of a woven or knitted fabric. This improves transparency prevention in a wet state. The titanium oxide content in the outermost layer of the sheath yarn is expressed relative to the mass of the outermost layer. If the content exceeds 2% by mass, the manufacturing processability deteriorates significantly. A more preferable titanium oxide content in the outermost layer is 0 to 1% by mass, and the outermost layer may contain no titanium oxide at all.

Furthermore, by having an inner layer with a titanium oxide content of 5 to 60% by mass, it is possible to improve transparency, particularly in a wet state. While it is possible to achieve normal transparency in a dry state with a titanium oxide content of less than 5% by mass, in a wet state, light scattering is suppressed, making the fabric more transparent. Therefore, in the present invention, an inner layer with a titanium oxide content of 5% by mass or more is essential. However, if the titanium oxide content of the inner layer exceeds 60% by mass, a problem of a drastic decrease in thread strength occurs. Therefore, the titanium oxide content of the inner layer is 5 to 60% by mass. A more preferable titanium oxide content of the inner layer is 11 to 35% by mass.

On the other hand, a major issue with blended yarns with a high titanium oxide content in the inner layer is fastness. Titanium oxide generates radicals when exposed to light, which oxidize and decompose polymers and dyes, causing problems such as a deterioration in lightfastness and yellowing. In particular, because the loops of the sheath yarn in blended yarns protrude from the fiber surface, they are particularly susceptible to problems such as a deterioration in lightfastness and yellowing, even if the outermost layer has a protective layer.

For this reason, in the sheath yarn of the mixed yarn of the present invention, rutile-type titanium oxide, which is less likely to generate radicals even when irradiated with light, is used in the inner layer. This makes it possible to prevent deterioration in light fastness and yellowing. Here, using the usual anatase-type titanium oxide has the advantage of being inexpensive to produce, but deterioration in light fastness and yellowing due to light irradiation are unavoidable. For this reason, in the mixed yarn of the present invention, rutile-type titanium oxide is used in the inner layer, which contains a high concentration of titanium oxide. Note that the outermost layer, which has a low titanium oxide content, may be either rutile-type or anatase-type.

The mass ratio of the outermost layer to the inner layer is preferably in the range of 10:90 to 40:60. This range of ratio is preferable in terms of achieving both transparency prevention and processability. A ratio of 15:85 to 25:75 is even more preferable.

Furthermore, the sheath yarn of the blended yarn of the present invention may have not only a two-layer structure consisting of an inner layer and an outermost layer, but also a three-layer structure or more. Increasing the number of layers is preferable because light is reflected at the layer interface, further improving the transparency prevention properties. From the standpoint of achieving both cost and transparency prevention performance, a three-layer structure consisting of an outermost layer, an inner layer, and an innermost layer located further inside the inner layer is preferred. In such a three-layer structure, as long as the mass ratio of the inner layer with a high titanium oxide content is 25% by mass or more of the blended yarn, transparency prevention performance can be maintained, so the titanium oxide content of the innermost layer can be low. In this case, the preferred ranges for the outermost layer:inner layer:innermost layer ratio are 10-40 for the outermost layer, 25-50 for the inner layer, and 20-60 for the innermost layer. In particular, a titanium oxide content of 2% by mass or less in the innermost layer is preferable because it improves color development in addition to transparency prevention properties. The preferred lower limit is 0% by mass, but from the standpoint of spinnability, the titanium oxide content in the innermost layer is preferably 0.1% by mass or more.

In the present invention, the sheath yarn may be a polyester fiber or a nylon fiber, but is preferably a polyester fiber with high refractive index and high crimp robustness. Specific examples include, but are not limited to, aromatic polyester fibers such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate, and aliphatic polyester fibers such as polylactic acid and polyglycolic acid. Of these, polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate fibers are preferred because they have excellent mechanical properties and durability and exhibit robust crimp. Furthermore, polyethylene terephthalate fibers are preferred because they exhibit the washing durability unique to polyester fibers.

Polyethylene terephthalate can be a polyester consisting of 90 mol% or more of ethylene terephthalate repeating units, with terephthalic acid as the primary acid component and ethylene glycol as the primary glycol component. It may also contain other copolymerizable components capable of forming ester bonds, provided that the effects of the present invention are not impaired. Examples of copolymerizable compounds include dicarboxylic acids such as isophthalic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, sebacic acid, and sulfonic acid.

The sheath yarn in the present invention preferably has a fiber cross-sectional flatness of 1.5 or less, which improves its opacity prevention properties when wet. One reason why opacity prevention properties decrease in a wet state compared to a dry state is that water penetrates into the interfiber voids, reducing light scattering and increasing transmitted light. For this reason, when a sheath yarn with a modified cross-section or flat cross-section with a flatness of more than 1.5 is used, the opacity prevention properties in a dry state improve, but tend to decrease in a wet state. A more preferred flatness of the sheath yarn is 1.0 or more and 1.4 or less.

The cross-sectional shape of the sheath yarn of the blended yarn of the present invention can be any shape, but a round shape is preferred for the reasons mentioned above. A hollow cross-sectional structure makes the cross-section prone to being crushed during the dyeing process, which can easily cause variations in flatness, so a substantially solid cross-sectional structure is preferred.

The mixed yarn of the present invention has stretchability, and by adjusting the properties of the core yarn to achieve unprecedented stretchability, the mixed yarn after processing can be given comfortable stretchability. In principle, this stretchability can be achieved if the core yarn has excellent stretch elongation and stretch recovery, but from the perspective of the bulkiness and firmness of the mixed yarn in subsequent processes, it is preferable that the fiber used for the core yarn in the present invention be a side-by-side or eccentric core-sheath composite fiber.

In addition, side-by-side and eccentric core-sheath composite fibers shrink and develop coil crimps during processing after dyeing, so using these fibers as the core yarn increases the coverage rate with the highly opaque sheath yarn during post-processing, allowing the sheath yarn to tightly coat the core yarn. This results in improved opaqueness and durability compared to when other fibers are used as the core yarn.

The term "side-by-side composite fiber" used here refers to a fiber in which polymer A and polymer B, which have different properties, are bonded together in the fiber cross section perpendicular to the fiber axis. Furthermore, "eccentric core-sheath composite fiber" refers to a fiber in which polymer A is positioned to the left or right of the center of gravity in the fiber cross section perpendicular to the fiber axis, and polymer B is positioned to cover it.

All of these fibers exhibit coil crimps that correspond to the shrinkage difference between polymer A and polymer B and the fiber diameter, and this coil crimp determines the stretch performance required for the core yarn of this invention. At the raw yarn stage, the fibers have a relatively flat fiber form, and developing a fine crimp after processing is advantageous for the durability of the blended yarn and its runnability during processing.

The combination of polymers used in these composite fibers is not particularly limited, but combinations such as high-viscosity polyethylene terephthalate/low-viscosity polyethylene terephthalate, polybutylene terephthalate (hereinafter referred to as "PBT")/polyethylene terephthalate (hereinafter referred to as "PET"), polytrimethylene terephthalate (hereinafter referred to as "PPT")/PET, and nylon 6/nylon 610 are preferred because they result in a large difference in the shrinkage properties of the two components, a large number of coils per unit fiber length, and a fine crimp pitch for the core yarn, resulting in a soft touch and excellent stretchability.

The weight ratio of the A polymer and B polymer components that make up the composite fiber is preferably in the range of 2:8 to 8:2. It is more preferably 4:6 to 6:4. Outside this range, the amount of either the high-shrinkage or low-shrinkage component will be less, which may result in coarse coil crimps.

The combined yarn of the present invention preferably has a total fineness of 20 to 250 dtex for both the core yarn and the sheath yarn, in order to impart firmness and transparency-preventing properties to the woven fabric. If the total fineness is less than 20 dtex, it may be difficult to obtain transparency-preventing properties. If the total fineness exceeds 250 dtex, the combined yarn may be too thick for use in outerwear.

The single core yarn fineness of the blended yarn of the present invention is preferably 1.0 to 10 dtex in order to impart a minimum amount of firmness and stiffness to the woven or knitted fabric. If the single core yarn fineness is less than 1.0 dtex, the fiber strength will be extremely weak, and the tear strength and burst strength of the woven or knitted fabric will tend to decrease. Furthermore, if the single core yarn fineness exceeds 10 dtex, the single core yarn will be too thick, which may make it difficult for the sheath yarn to entangle.

The single sheath yarn fineness of the blended yarn of the present invention is preferably 0.5 to 5 dtex in order to impart a soft feel to the woven or knitted fabric. If the single yarn fineness is less than 0.5 dtex, the fiber strength will be extremely weak, and pilling and snagging will tend to decrease. If the single yarn fineness exceeds 5 dtex, the single yarn may be too thick and may not easily entangle with the core yarn.

Furthermore, the number of loop fluffs formed in the surface layer of the blended yarn of the present invention is preferably 10 to 300 loop fluffs of 0.6 mm or more per m in order to achieve a balance between texture, opacity resistance, and quality. Having 10 or more loop fluffs of 0.6 mm or more per m allows for a woven or knitted fabric with a cotton-like, soft texture. Here, if the number of loop fluffs is less than 10 per m, the woven or knitted fabric may have a plain, lacking fluffy feel. On the other hand, if it exceeds 300 per m, the inter-fiber voids increase, the opacity resistance in wet conditions decreases, and the loops are more likely to be squeezed by the guide, which may result in yarn breakage, poor unwinding, etc. A more preferred number of loop fluffs is 30 to 250 per m.

The heat shrinkage rate of the sheath yarn of the blended yarn of the present invention is preferably 0 to 5% in order to maintain transparency in a wet state. If the heat shrinkage rate of the sheath yarn exceeds 5%, the individual loops of the sheath yarn formed and fixed in the nozzle section tend to come apart. This can result in gaps between the fibers, which can be a factor in reducing transparency in a wet state. On the other hand, if the heat shrinkage rate of the sheath yarn is less than 0%, the loops of the sheath yarn tend to become larger, reducing snags.

It is also preferable that the core yarn heat shrinkage rate of the blended yarn of the present invention is 0 to 10%. If the core yarn heat shrinkage rate exceeds 10%, the sheath yarn loops will become larger and snags will tend to decrease. On the other hand, if the core yarn heat shrinkage rate is less than 0%, distortion will be more likely to occur in woven or knitted fabrics.

In addition, the blended yarn of the present invention is preferably used without twist to achieve a fluffy feel, but it may also be subjected to twisting processing. The preferred twist number is 50 to 1,000 T/m.

Next, we will explain the manufacturing methods for the blended yarn and woven/knitted fabrics of the present invention.

First, when spinning the raw yarn that will become the base yarn for the blended yarn of the present invention, either a highly oriented undrawn yarn or a drawn yarn may be used. However, in order to reduce the thermal shrinkage rate of the sheath yarn, it is preferable to use a highly oriented undrawn yarn in which the amorphous portion is highly oriented, and the preferred spinning speed is 2800 to 3500 m/min.

To reduce the heat shrinkage rate of the sheath yarn, it is preferable to heat treat the sheath yarn at a high temperature before blending. A hollow heater is preferably used for the heat treatment to prevent fuzzing due to heater contamination, and the preferred heater temperature is 180-230°C. The heat shrinkage rate of the sheath yarn is adjusted appropriately so that it is 0-5%.

Next, any nozzle can be selected to intertwine the core yarn and sheath yarn, but a turbulent flow processing nozzle such as a Taslan nozzle, which can form stable loops, is preferred. Loops can be formed in the sheath yarn by adjusting the overfeed of the core yarn and sheath yarn supplied to the nozzle. To form loop fuzz of 0.6 mm or more in the range of 10 to 300 per meter, the overfeed difference between the sheath yarn and core yarn is preferably 3 to 25%. Furthermore, the entanglement pressure is preferably 0.1 to 1.0 MPa, and more preferably 0.5 to 0.9 MPa.

When blending with a Taslan nozzle, water can be added to the core yarn to more firmly entangle the loops. It is acceptable to add water, as the sheath yarn will be more firmly entangled, improving physical properties such as anti-transparency and snag/pilling resistance.

Also, before blending, the sheath yarn can be heat-treated and drawn at a low magnification using a hot pin to impart thick and thin sections to the yarn. By imparting thick and thin filaments and creating a random flecked texture, a more cotton-like surface can be achieved, but this increases the dye adsorption of the thick sections and reduces color fastness. Therefore, the preferred hot pin drawing conditions are a magnification of 1.2 to 1.8 times and a hot pin temperature range of 70 to 90°C.

When blending fibers, a faster processing speed is preferable as it increases productivity, but considering stable processing, a speed of 100 to 800 (m/min) is preferred.

Furthermore, the blended yarn of the present invention preferably has a stretching extension rate of 20 to 150% after tensioning at 0.5 cN/dtex. By controlling the fluid turbulence treatment conditions and setting the stretching extension rate in this range so as not to inhibit the development of three-dimensional coil crimp, good stretchability can be obtained when the yarn is made into a woven or knitted fabric. If the stretching extension rate is less than 20%, the woven or knitted fabric may not have sufficient stretchability. If the stretching extension rate exceeds 150%, the stretchability may be too strong, causing unevenness on the surface of the woven or knitted fabric, and a soft texture may not be achieved. The preferred stretching extension rate is 20 to 125%, and more preferably 20 to 100%.

The mixed yarn of the present invention produced in this manner is made into woven or knitted fabrics using known weaving and knitting methods. In the present invention, woven fabrics and knitted fabrics are collectively referred to as "woven or knitted fabrics." There are no restrictions on the structure or density of the woven or knitted fabrics of the present invention. To improve transparency in a wet state, woven or knitted fabrics using 30% by mass or more of the mixed yarn of the present invention are preferred. Cellulose-based filaments or spun yarns in particular have low transparency in a wet state, but by interweaving or interknitting the woven or knitted fabric with the mixed yarn of the present invention in an amount of 30% by mass or more, for example, the transparency in a wet state can be improved.

The loom used for weaving can be any commonly used model, such as a conventional loom, rapier loom, water jet loom, or air jet loom, without any particular limitations.

In addition, commercially available knitting machines such as circular knitting machines, tricot machines, and Raschel machines can be used for knitting. When the blended yarn of the present invention is used as at least a part of the knitting yarn, it is preferable to optimize the tension of each machine during knitting.

Knit structures include, but are not limited to, jersey, kanoko, smooth, rib, punch, rib, mock lody, bonded reversible, half, denbigh, satin, and atlas. However, to maximize the transparency prevention effect, when the blended yarn of the present invention is interwoven with other fibers, it is preferable to use a structure in which the blended yarn is positioned on the surface and the other fibers are not exposed on the surface. In the case of circular knitting, regardless of whether a single or double knitting machine is used, it is more preferable to use a structure in which the front and back sides can be completely separated, such as reversible jersey, reversible kanoko, bonded structure, or inlay structure. In the case of warp knitting, it is more preferable to use knitting conditions in which the blended yarn of the present invention is positioned on the front reed and the blended yarn is positioned on top of other fibers on both the front and back sides. Weaves are not limited to double denbigh, half, satin, and atlas.

The dyeing process can be carried out in accordance with the dyeing process and conditions used for woven and knitted fabrics made from general polyester or nylon blended yarns. If necessary, heat-resistant, shrink-proof, wrinkle-resistant, softening, weight reduction, and other processing may also be applied.

The woven or knitted fabric of the present invention may also contain small amounts of resin materials, such as softeners, radical scavengers, antioxidants, fluorescent whitening agents, antibacterial agents, ultraviolet absorbers, light stabilizers, flame retardants, matting agents, antistatic agents, hard finishing agents, shape stabilizers, water repellents, and water absorbents, as needed.

The woven and knitted fabrics of the present invention are preferred in that they have excellent moisture absorption and quick-drying properties, with a water absorption rate of within 5 seconds and a residual moisture content of 30% or less after 60 minutes. These woven and knitted fabrics of the present invention are preferred in that they are cotton-like yet possess moisture absorption and quick-drying properties that cannot be achieved with cotton.

Furthermore, it is preferable that the woven or knitted fabric of the present invention has transparency resistance of grade 4 or higher in both the dry and wet states based on JIS L1923:2017 "Method for evaluating the transparency resistance of textile products" Method A (visual method), as this provides excellent transparency resistance in both the dry and wet states.

The present invention will now be described in detail using examples, but the present invention is not limited to these examples. The various measurement methods used in the present invention are as follows:

1. Fineness A skein of 100 rounds was prepared using a measuring machine with a frame circumference of 1.0 m, and the fineness was measured according to the following formula.
Fineness (dtex) = Weight of skein (g) for 100 times x 100

2. Stretching Elongation The fabric is wound 10 times around a measuring machine with a frame circumference of 0.8 m under a tension of 90 mg/dtex to form a skein, which is then hung from a rod of 2 cm or less and left for approximately 24 hours. This skein is heat-treated at 90°C for 20 minutes under no tension, and then hung from a rod of 2 cm or less and left under no tension. After approximately 12 hours, the skein length is measured and defined as L. A measurement load (g) of 90 mg/dtex is then applied, and the skein length is measured and defined as L1. The stretching elongation is calculated using the following formula. Measurements are made at 10 points, and the average value is defined as the stretching elongation.
・Stretching and elongation rate (%) = {(L-L1)/L}×100

3. Loop fluff count
The number of loop fluffs protruding 0.6 mm or more from the yarn surface of the mixed yarn was measured for 2 minutes using a photoelectric fluff measuring machine (TORAYFRAY COUNTER) under conditions of a yarn speed of 10 m/min and a running yarn tension of 0.1 g/d, and the number of loop fluffs per meter was calculated.

4. Titanium oxide content The sheath yarn taken out from the blended yarn was sampled at five locations in the longitudinal direction, and after carbon deposition, quantitative elemental analysis of the outermost layer and inner layer was carried out using a JEOL electron probe microanalyzer (FE-EPMA) JXA-8530F at an acceleration voltage of 15 kV and a probe current of 40 nA, and the average titanium oxide content of each was calculated from the content of Ti (titanium) element.

5. Transparency The transparencies in the dry and wet states were determined based on JIS L1923:2017 "Method for evaluating the transparencies of textile products" Method A (visual method). Grade 4 or higher was set as the pass criterion.

6. Lightfastness The lightfastness was determined based on JIS L0842:2004: "Test method for color fastness to ultraviolet carbon arc lamp light." Grade 3 or higher was set as the pass standard.

7. Processability The operability of the mixed fiber processing was evaluated (36 spindles, 5 days), and the yarn breakage rate was judged according to the following criteria. ⊚ and ○ were the pass criteria.
◎: Thread breakage rate is less than 3%. ○: Thread breakage rate is 3% or more but less than 5%. △: Thread breakage rate is 5% or more but less than 10%. ×: Thread breakage rate is 10% or more.

8. Flatness The mixed yarn was sampled at five locations in the fiber axis direction, embedded in resin, and cut out to obtain cross-section observation samples, and each sample was micrographed. For all the fiber cross sections photographed, the ratio A/B of the length (A) of the longest part (major axis) to the maximum length (B) of the minor axis perpendicular to the major axis was measured, and the ratio was expressed as the average of all the measured values.

9. Quick drying (diffusible residual moisture content)
After measuring the mass (W) of a 10 cm x 10 cm test piece, 0.6 ml of water was dropped onto the test piece and the mass (W0) was measured. The test piece was hung to dry under standard conditions (20°C, 65% RH) and the mass (Wt) was measured every 5 minutes, and the diffusible residual moisture content (%) was calculated every hour using the following formula. The obtained residual moisture content was linearly approximated, and a test piece that took 55 minutes or less to reach a residual moisture content of 10% was deemed to have passed the test.
Diffusible residual moisture content (%) = {(Wt-W)/(W0-W)} x 100

10. Water Absorbency Water absorbency was measured by the dropping method described in JIS L 1907:2010 "Testing Method for Water Absorbency of Textile Products." A time of 5 seconds or less was set as the passing criterion.

11. Stretchability: Measured by JIS B method (grab method) described in JIS L 1096:2010 "Testing methods for woven and knitted fabrics" for tensile strength and elongation. A passing criterion was 40% or more in both the warp and weft directions, with passing criterion being good and failing criterion being unsatisfactory.

Hereinafter, Example 7 will be read as Reference Example 1.
Example 1
A polyethylene terephthalate fiber having a round cross section, in which an outermost layer containing 0.2% by mass of anatase-type titanium dioxide and an inner layer containing 30% by mass of rutile-type titanium dioxide are arranged in a mass ratio of 20:80, is spun at a spinning speed of 3000 (m/min) to obtain a fiber having a fineness of 110 dtex-36F and an elongation of 170%.
Highly oriented undrawn yarn A was obtained.

PTT/PET were arranged side-by-side in a mass ratio of 50:50, spun at a spinning speed of 1500 (m/min), and drawn at 4000 (m/min) to obtain drawn yarn B with 56 dtex-24F and an elongation of 36%.

Using a blending machine, the highly oriented undrawn yarn A was drawn at a hollow heater temperature of 200°C and a draw ratio of 1.4x before blending. It was then fed as a sheath yarn to a Taslan nozzle at an overfeed rate of 14% and blended with drawn yarn B (core yarn) fed at an overfeed rate of 10% at an entanglement pressure of 0.75 (MPa) and a processing speed of 400 m/min, resulting in a blended yarn with a fineness of 150 dtex-60F, a flatness of 1.4, a number of loop fluffs of 0.6 mm or more per meter (105/m), and a stretch elongation of 38.2%. The process was very smooth with little yarn breakage.

Next, the raw yarn was used to knit a plain stitch on a single circular knitting machine (Fukuhara, XA-3FA, 28G, 30 x 2.54 mm). The resulting knitted fabric was then continuously scoured at 98°C, liquid flow relaxed at 120°C, and finish set at 160°C, resulting in a knitted fabric with a width of 133 cm, a welting density of 47W, and a course density of 70C.

The resulting knitted fabric had excellent opacity in both dry and wet conditions, and also had good lightfastness, stretchability, and quick-drying properties, making it an ideal opacity material with a soft, cotton-like texture.

Example 2
A mixed yarn having a number of loop fluffs of 0.6 mm or more: 168/m and a stretch elongation rate of 38.5% was obtained in the same manner as in Example 1, except that the content of rutile-type titanium oxide was 15% by mass and the overfeed rate of highly oriented undrawn yarn A was 16%. The processability was very good with little yarn breakage.

Next, a knitted fabric was produced using the same process as in Example 1.

The resulting knitted fabric had excellent opacity in both dry and wet conditions, and also had good lightfastness, stretchability, and quick-drying properties, making it an ideal opacity material with a soft, cotton-like texture.

Example 3
A mixed yarn having a fineness of 150 dtex-60F, a flatness of 1.2, a number of loop fluffs of 0.6 mm or more: 68/m, and a stretch elongation of 34.1% was obtained in the same manner as in Example 2, except that the drawing speed of drawn yarn B was set to 3500 (m/min), a PTT/PET eccentric core-sheath type drawn yarn having an elongation of 32% was used, and the overfeed rate of highly oriented undrawn yarn A was set to 13%. The processability was very good with little yarn breakage.

Next, a knitted fabric was produced using the same process as in Example 1.

The resulting knitted fabric had excellent opacity in both dry and wet conditions, and also had good lightfastness, stretchability, and quick-drying properties, making it an ideal opacity material with a soft, cotton-like texture.

Example 4
As drawn yarn B, PBT/PET was arranged side-by-side in a mass ratio of 50:50, spun at a spinning speed of 1200 (m/min), and drawn at 3500 (m/min) to obtain drawn yarn B of 56 dtex-24F and elongation of 32%.

Using a blending machine, the same highly oriented undrawn yarn A as in Example 2 was subjected to low-magnification heat treatment and drawing at 1.4 times the hot pin temperature of 80°C before blending to form a thick and thin section. It was then heat-treated at a fixed length with a hollow heater temperature of 180°C, and then fed as a sheath yarn to a Taslan nozzle at an overfeed rate of 19%. Blending processing was then carried out with drawn yarn B (core yarn) fed at an overfeed rate of 10% at an entanglement pressure of 0.75 (MPa) and a processing speed of 400 m/min, resulting in a blended yarn with a fineness of 150 dtex-60F, a flatness of 1.4, a number of loop fluffs of 0.6 mm or more per meter of 282/m, and a stretch elongation of 29.2%. The processability was excellent, with little yarn breakage.

Next, a knitted fabric was produced in the same process as in Example 1.
The obtained knitted fabric had excellent transparency-proof properties in both dry and wet conditions, and also had good lightfastness, stretchability, and quick-drying properties. It was suitable as a transparency-proof material with a cotton-like, soft texture.

Example 5
A mixed yarn having a fineness of 150 dtex-60F, a flatness of 1.4, a number of loop fuzzes of 0.6 mm or more of 110/m, and a stretch elongation of 38.4% was obtained in the same manner as in Example 1, except that a highly oriented undrawn yarn having a fineness of 110 dtex-36F and an elongation of 170% was used, which was obtained by spinning, at a spinning speed of 3,000 m/min, polyethylene terephthalate having a round cross section, with an outermost layer containing 0.7% by mass of anatase titanium dioxide, an inner layer containing 20% by mass of rutile titanium dioxide, and an innermost layer containing 0.7% by mass of anatase titanium dioxide in a mass ratio of 20:30:50. The mixed yarn had little yarn breakage and was very good in processability.

Next, a knitted fabric was produced in the same process as in Example 1.
The obtained knitted fabric had excellent transparency-proof properties in both dry and wet conditions, and also had good lightfastness, stretchability, and quick-drying properties. It was suitable as a transparency-proof material with a cotton-like, soft texture.

Example 6
Nylon 6 having a round cross section, in which an outermost layer containing 0.2% by mass of anatase titanium oxide and an inner layer containing 30% by mass of rutile titanium oxide were arranged in a mass ratio of 20:80, was spun at a spinning speed of 3,300 (m/min) to obtain drawn yarn C having a fineness of 67 dtex-36F and an elongation of 55%. Subsequently, drawn yarn D having an eccentric core-sheath type of 66 dtex-24F and an elongation of 35% was obtained, in which nylon 6/nylon 610 were arranged in a mass ratio of 50:50.

Using a blending machine, drawn yarn C was supplied as a sheath yarn to a Taslan nozzle at an overfeed rate of 40%, and blended with another drawn yarn D (core yarn) supplied at an overfeed rate of 3% at an entanglement pressure of 0.75 MPa and a processing speed of 400 m/min, resulting in a blended yarn with a fineness of 123 dtex-60F, flatness of 1.2, loop fuzz count of 144/m, and a stretch elongation of 25.8%. The blending process was very smooth, with little yarn breakage.

The raw yarn was then used to knit a plain stitch on a single circular knitting machine (Fukuhara, XA-3FA, 28G, 30 x 2.54mm). The resulting knitted fabric was then subjected to continuous scouring at 98°C, liquid flow relaxation at 98°C, and finish setting at 130°C, resulting in a product with a width of 133cm, a welting density of 47W, and a course density of 70C.

The resulting knitted fabric had excellent opacity in both dry and wet conditions, and also had good lightfastness, stretchability, and quick-drying properties, making it an ideal opacity material with a soft, cotton-like texture.

<Comparative Example 1>
A mixed yarn having a fineness of 110 dtex-36F, a flatness of 1.4, a number of loop fluffs of 0.6 mm or more of 105/m, and a stretch elongation of 38.6% was obtained in the same manner as in Example 1, except that an anatase type titanium oxide was used for the inner layer. The processability was very good with little yarn breakage.

Next, a knitted fabric was produced using the same process as in Example 1.

The resulting knitted fabric had excellent opacity in both wet and dry conditions, good stretchability and quick-drying properties, and a soft, cotton-like texture. However, it was subject to significant discoloration due to light, making it unsuitable for use in clothing.

<Comparative Example 2>
A knitted fabric was produced in the same manner as in Example 1, except that highly oriented undrawn yarn A was spun using polyethylene terephthalate with a circular cross section, in which an outermost layer contained 15% by mass of anatase-type titanium oxide and an inner layer contained 0.7% by mass of rutile-type titanium oxide were arranged in a mass ratio of 20:80.

The resulting knitted fabric had excellent opacity in both dry and wet conditions, good stretchability and quick-drying properties, and a soft, cotton-like texture. However, it showed some noticeable discoloration in light, making it unsuitable as a clothing material.

Example 7
A mixed yarn having a loop fluff count of 0.6 mm or more: 375/m and a stretch elongation rate of 37.9% was obtained in the same manner as in Example 1, except that the overfeed rate of the highly oriented undrawn yarn A was 24% and the entanglement pressure with the drawn yarn B (core yarn) was 0.77 (MPa). The processability was poor, with many yarn breakages due to contamination of the nozzle and guide, making production difficult.

Next, a knitted fabric was produced using the same process as in Example 1.

The resulting knitted fabric had excellent opacity in both dry and wet conditions, and also had good lightfastness, stretchability, and quick-drying properties. However, it had a lot of surface fuzz and was inferior in softness and texture to the knitted fabrics obtained in Examples 1 to 6. However, it was within the range of usable cotton-like materials and could be used for clothing if the application was selected.

<Comparative Example 3>
A mixed yarn having a fineness of 150 dtex-60F, a flatness of 1.2, a number of loop fluffs of 0.6 mm or more of 98/m, and a stretch elongation of 38.3% was obtained in the same manner as in Example 1, except that highly oriented undrawn yarn A was spun using polyethylene terephthalate having a round cross section, in which an outermost layer contained 0.2% by mass of anatase titanium oxide and an inner layer contained 2.3% by mass of rutile titanium oxide in a mass ratio of 20:80. The yarn had little breakage and was very good in processability.

Then, a knitted fabric was produced using the same process as in Example 1.

The resulting knitted fabric had good lightfastness, stretchability, and quick-drying properties, and had a soft, cotton-like texture, but its transparency was insufficient in both dry and wet conditions, making it unsuitable as a transparency-blocking material.

<Comparative Example 4>
Highly oriented undrawn yarn A and drawn yarn B were obtained in the same manner as in Example 1.

Using a blending machine, the highly oriented undrawn yarn A was stretched at a hollow heater temperature of 200°C and a draw ratio of 1.4x before blending. It was then interlaced with drawn yarn B, also with an overfeed rate of 0.5%, at an interlacing pressure of 0.2 (MPa) and a processing speed of 550 (m/min), to obtain a blended yarn with a fineness of 150 dtex-60F, a flatness of 1.2, a number of loop fuzzes of 0.6 mm or more per meter, and a stretch elongation of 39.5%. The process was very smooth, with little yarn breakage.

Next, a knitted fabric was produced using the same process as in Example 1.

The resulting knitted fabric had good lightfastness, stretchability, and quick-drying properties, but lacked volume and was far from soft to the touch. Its opacity in both dry and wet conditions was insufficient, making it unsuitable as an opacity-resistant material.

Comparative Example 5
A false twist textured yarn of 56 dtex-24F with a round cross section and an elongation of 30% was obtained, which was made only of PET.

Using a blending machine, the same highly oriented undrawn yarn A as in Example 1 was drawn at a hollow heater temperature of 200°C and a draw ratio of 1.4x before blending. It was then fed as a sheath yarn to a Taslan nozzle at an overfeed rate of 13% and blended with the false twist textured yarn (core yarn) fed at an overfeed rate of 9% at an entanglement pressure of 0.77 (MPa) and a processing speed of 3,800 m/min, resulting in a blended yarn with a fineness of 150 dtex-60F, a flatness of 1.0, a number of loop fuzzes of 0.6 mm or more per meter of 90, and a stretch elongation of 31.1%. The process was very smooth with little yarn breakage.

Next, a knitted fabric was produced using the same process as in Example 1.

The resulting knitted fabric had excellent opacity in both dry and wet conditions, and also had good lightfastness and quick-drying properties. However, the texture was rough and hard, and it had insufficient stretch, making it unsuitable as an opacity material with a soft, cotton-like texture.

The present invention provides a blended yarn that exhibits excellent wet-state opacity and fastness, as well as ease of manufacturing, and a highly stretchable woven or knitted fabric that has a cotton-like, soft feel. As a result, such woven or knitted fabrics not only exhibit excellent opacity, but also excellent heat and UV protection, making them suitable for use in casual clothing, formal clothing, uniforms, sportswear, and more.

Claims (7)

A mixed yarn comprising a core yarn and a sheath yarn, the core yarn being a side-by-side type or an eccentric core-sheath type composite fiber, the sheath yarn having an outermost layer portion having a titanium oxide content of 0 to 2% by mass and an inner layer portion having a titanium oxide content of 5 to 60% by mass, the titanium oxide in the inner layer portion being of rutile type, and covering the composite fiber ,
The mass ratio of the outermost layer part to the inner layer part of the sheath yarn is 15:85 to 25:75.
the total fineness of the blended yarn is 20 to 250 dtex for both the core yarn and the sheath yarn, and the single yarn fineness of the sheath yarn is 0.5 to 5 dtex;
The number of loop fluffs of 0.6 mm or more is present in the surface layer part of the mixed yarn at a rate of 10 to 300 pieces/m,
A blended yarn having a stretch elongation rate of 20 to 100% after tensioning at 0.5 cN/dtex . 2. The mixed yarn according to claim 1 , wherein the single core yarn fineness of the mixed yarn is 1.0 to 10 dtex . The mixed yarn according to claim 1 or 2, wherein the sheath yarn has a cross-sectional flatness of 1.5 or less . A blended yarn according to any one of claims 1 to 3, having an innermost layer having a titanium oxide content of 0 to 2% by mass inside the inner layer having a titanium oxide content of 5 to 60% by mass. A woven or knitted fabric made using the blended yarn described in any one of claims 1 to 4. The woven or knitted fabric described in claim 5 has water absorption within 5 seconds and a residual moisture content of 30% or less after 60 minutes. The woven or knitted fabric according to claim 5 or 6, wherein the opacity of both the dry and wet states is grade 4 or higher based on JIS L1923:2017 "Method for evaluating the opacity of textile products" Method A (visual method).