KR102593079B1 - Polyamide multifilament and lace knitted fabric using it - Google Patents

Abstract

One embodiment of the present invention provides a high-strength polyamide multifilament that is excellent in durability, has a beautifully shiny pattern, and provides a lace knit fabric with excellent softness. One embodiment of the present invention relates to a polyamide multifilament characterized by a single yarn fineness of 0.8 to 7 dtex, a strength of 7.5 to 8.5 cN/dtex, and a nodule strength of 6.0 to 7.5 cN/dtex.

Description

Polyamide multifilament and lace knitted fabric using it

The present invention relates to polyamide multifilaments suitable for lace knitting. More specifically, it relates to a polyamide multifilament that can provide a lace knitted fabric with excellent durability, beautifully shiny patterns, and good feel when used as a branch of lace paper.

Polyamide fibers and polyester fibers, which are synthetic fibers, are widely used for medical and industrial purposes because they have excellent mechanical and chemical properties. In particular, polyamide fibers have excellent properties in terms of unique softness, high strength, color development when dyeing, heat resistance, and hygroscopicity, and are widely used for general medical purposes such as stockings, innerwear, and sportswear.

As a consumer need for lace, there was a demand for lace with beautifully shiny lace patterns and a soft feel. In order for the lace pattern to shine beautifully, it is necessary to fine-fine the threads that make up the ground tissue, but since the strength of the threads decreases as the fineness increases, higher strength was desired. In addition, as the fineness of the threads constituting the ground tissue increases, the proportion of coarse threads increases, and the stress acting on the interlaced portion of the ground fiber becomes stronger, so it was also desired to strengthen the durability of the interlaced portion. In addition, in order to soften the feel of the lace, there was a strong demand for finer single yarns of the yarns that make up the ground tissue.

With regard to increasing the strength of polyamide fibers, for example, Patent Document 1 proposes nylon 6 fiber for fishing nets with a fineness of 250 to 4400 dtex, which is excellent in durability and weather resistance, and also produces high strength and high toughness nets, and fishing nets using the same. It is done.

Patent Document 2 discloses polyamide fibers with a fineness of 300 to 1000 dtex, which have excellent shock absorption against shear stress and multi-directional impacts and have excellent durability and fatigue resistance when subjected to piece processing and used as industrial materials. A knitted fabric using is proposed.

Japanese Patent Publication No. 2008-31572 Japanese Patent Publication No. 2004-11082

However, since the fibers described in Patent Documents 1 and 2 have a fine fineness, the transparency of the lace is not obtained and they are not suitable for lace knitting. In addition, because it was a single yarn with a high degree of fineness, it could not satisfy the tactile feel of lace knitted fabric.

The present invention solves the above problems, and its object is to provide a high-strength polyamide multifilament with excellent durability even when the fineness of the yarn is fine or the fineness of the single yarn is increased. More specifically, polyamide multifilament with high strength and high nodule strength provides excellent passability and product quality, and finer and single yarn finer fines are possible while maintaining the same level of strength as before, and the durability of the lace is improved. While maintaining the transparency of the lace yarn, the pattern shines beautifully and provides lace knitted fabric with excellent tactile feel.

In order to solve the above problems, the present invention adopts the following configuration.

(1) Polyamide multifilament characterized by a single yarn fineness of 0.8 to 7 dtex, a strength of 7.5 to 8.5 cN/dtex, and a nodule strength of 6.0 to 7.5 cN/dtex.

(2) In (1),

A polyamide multifilament characterized by a tensile strength of 6.1 to 7.5 cN/dtex at 15% elongation.

(3) In (1) or (2),

Polyamide multifilament characterized by a total fineness of 20 to 44 dtex.

(4) A lace knitted fabric using the polyamide multifilament according to any one of (1) to (3) as a lace yarn.

(5) A method for producing polyamide multifilaments in which the polyamide resin is melted, each filament discharged from the spinneret is cooled, solidified, and stretched,

A spinneret for discharging molten polyamide resin to form a filament, a heating passage for slowly cooling the filament, a cooling device for cooling and solidifying the filament, and a fluid swirling nozzle for imparting convergence properties to the yarn by swirling flow. Using a polyamide multifilament manufacturing device comprising at least a device, a pulling roller for taking and stretching the filament, and a stretching device for stretching the filament,

In addition, the method for producing polyamide multifilament according to any one of (1) to (3), characterized in that the following conditions (A) to (D) are simultaneously satisfied.

(A) The heating tank is installed on top of the cooling device.

(B) The fluid swirling nozzle device is installed on the upper part of the receiving roller.

(C) The stretching device is a multi-stage stretching device with two or more stages.

(D) Low-relaxation heat treatment immediately after multi-step stretching

(6) In (5),

A method for producing polyamide multifilament, characterized in that a relaxation heat treatment is performed between a stretching roller and a relaxation roller at a relaxation rate of 0 to 1.5% and a heat setting temperature of 150 to 200 ° C.

(Effects of the Invention)

The polyamide multifilament of the present invention is a polyamide multifilament with high strength and high nodular strength. In addition, the polyamide multifilament of the present invention has excellent high-order passability and product quality, and while maintaining the durability of the lace, the transparency of the lace fiber allows the pattern to shine beautifully and a lace knitted fabric with excellent tactile feel can be obtained.

Figure 1 shows one embodiment of a manufacturing apparatus that can be suitably used for manufacturing polyamide multifilament, which is one embodiment of the present invention.
FIG. 2 shows an embodiment of a manufacturing apparatus exemplified for comparison in the production of polyamide multifilament, which is an embodiment of the present invention.
Figure 3 is a schematic cross-sectional model showing a spinneret and a heating tube that can be suitably used in the production of polyamide multifilament, which is one embodiment of the present invention.
Figure 4 shows an embodiment of a turning nozzle that can be preferably used in the production of polyamide multifilament, which is an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

The polyamide multifilament, which is one embodiment of the present invention, is composed of polyamide. Such polyamide is a resin composed of a high molecular weight body in which so-called hydrocarbon groups are linked to the main chain through amide bonds.

These polyamides are excellent in spinning properties and mechanical properties, and polycaproamide (nylon 6) and polyhexamethylene adipamide (nylon 66) are mainly preferred. In addition, polycaproamide (nylon 6) is more preferable because it is difficult to gel and has good spinning properties.

The polycaproamide has ε-caprolactam as a structural unit, and more than 80 mol% of it is composed of ε-caprolactam. The polycaproamide preferably consists of 90 mol% or more of ε-caprolactam.

In addition, the polyhexamethylene adipamide has hexamethylenediammonium adipate as a structural unit, and more than 80 mol% of it is composed of hexamethylenediammonium adipate. The polyhexamethylene adipamide is preferably composed of 90 mol% or more of hexamethylene diammonium adipate.

Other components are not particularly limited, but examples include polydodecanoamide, polyhexamethylene adipamide, polyhexamethylene azelamide, polyhexamethylene sebacamide, polyhexamethylene dodecanoamide, and polymethoxylylene. Examples include units such as aminocarboxylic acid, dicarboxylic acid, and diamine, which are monomers constituting adipamide, polyhexamethylene terephthalamide, and polyhexamethylene isophthalamide.

In addition, in order to effectively exhibit the effects of the present invention, it is preferable that the polyamide does not contain various additives such as a matting agent typified by titanium oxide. However, various additives, such as heat resistant agents, may be contained as necessary within a range that does not impair the effects of the present invention. Additionally, the content may be mixed as needed in the range of 0.001 to 0.1% by weight based on the polymer.

The polyamide multifilament, which is one embodiment of the present invention, is characterized by having single yarn fineness, strength, and nodule strength all within the above-mentioned specific ranges.

In general, by reducing the fineness of polyamide multifilament, the transparency of the lace fibers increases and a lace knitted fabric with a beautifully shining pattern is obtained, but the product strength is lowered and the durability of the lace is reduced. Additionally, as the thread ratio of the soldier increases, the stress acting on the branch at the abutment increases. Therefore, in order to maintain durability, it is necessary to increase the strength and nodule strength. Additionally, in order to make the lace soft to the touch, it is necessary to thin the single yarn fineness.

Therefore, the present inventors carefully studied, and in order to provide a lace knitted fabric that has excellent feel and durability, increases the transparency of the lace yarns, and makes the pattern shine beautifully, it is necessary to set the single yarn fineness, strength, and nodule strength within the above-mentioned specific ranges. I discovered something important.

The polyamide multifilament of one embodiment of the present invention has a single yarn fineness of 0.8 to 7 dtex. By setting it within this range, it becomes a lace with a soft touch. If the single yarn fineness is greater than 7dtex, the feel of the lace becomes hard. If the single yarn fineness is less than 0.8dtex, the strength decreases due to high tension in the spinning process and high-level processing process, abrasion of the guide, etc., fluff is likely to occur, yarn breakage increases in the high-level processing process, and product strength and quality decrease. It deteriorates. Preferably, it is 3.0 to 6.6 dtex.

The polyamide multifilament of one embodiment of the present invention has a strength of 7.5 to 8.5 cN/dtex. By setting this range, the durability of the lace can be improved and fineness can be increased to achieve transparency. If the strength is less than 7.5 cN/dtex, the durability of the lace deteriorates. If the strength is greater than 8.5 cN/dtex, fluff is likely to occur due to high tension in the spinning process or high-level processing process and abrasion of the guide, etc., which increases thread breakage in the high-level processing process and reduces quality. Preferably, it is 7.7 to 8.2 cN/dtex.

Lace knitting has a special knitting structure, so the force is concentrated at the intersection of the branch and branch sections. Therefore, it is important for the durability of the lace to increase not only the strength in the fiber axis direction described above but also the nodule strength. That is, in addition to the strength in the fiber axis direction, improving the strength of the stress concentration area at the intersection point improves the durability of the lace.

In addition, increasing the nodule strength is particularly effective in fine-fine polyamide multifilament. In order to realize the transparency of the lace branch, when the fineness of the branch is increased, the yarn ratio in the joint area increases, and as a result, the stress acting on the abutment area of the branch increases. Therefore, by increasing the nodule strength, it becomes possible to increase the fineness.

The polyamide multifilament of one embodiment of the present invention has a nodule strength of 6.0 to 7.5 cN/dtex. By setting this range, the durability of the lace can be improved and the fineness can be increased to achieve transparency. If the nodule strength is less than 6.0 cN/dtex, the filament cannot withstand the stress acting on the intersection point of the branch and disease parts, so it breaks, and the durability of the lace is reduced. In addition, the larger the nodule strength is, the more desirable it is, but the upper limit in the present invention is 7.5 cN/dtex. Preferably, it is 6.3 to 7.5 cN/dtex.

The polyamide multifilament, which is an embodiment of the present invention, preferably has a tensile strength at 15% elongation (hereinafter sometimes referred to as “15% strength”), which is an indicator of yarn physical properties, of 6.1 to 7.5 cN/dtex. do. The 15% strength was measured according to JIS L1013 (2010) tensile strength and elongation, a tensile strength-elongation curve was drawn, and the tensile strength (cN) at 15% elongation was divided by the total fineness. The 15% strength is a value that simply represents the fiber modulus. A high 15% strength indicates a high gradient in the tensile strength-elongation curve and a high fiber modulus. On the other hand, if the 15% strength is low, the gradient of the tensile strength-elongation curve is low and the fiber modulus is low.

As described later, the polyamide multifilament, which is an embodiment of the present invention, is subjected to multi-step, high-magnification stretching, and high fiber modulus is realized by high-magnification stretching. In particular, multi-step stretching is performed to achieve high fiber modulus while also suppressing the generation of fluff. .

The polyamide multifilament, which is an embodiment of the present invention, improves product quality by setting the 15% strength to 6.1 to 7.5 cN/dtex. By setting the 15% strength to 6.1 cN/dtex or more, changes in fiber structure and crystal orientation during the dyeing process are small, shrinkage of the fiber is suppressed, and it is easy to maintain fiber rigidity. In other words, dimensional changes and uneven shrinkage during heat setting in the lace manufacturing process are reduced, the surface of the fabric is smooth and beautiful, and the quality of the product is improved. By setting the 15% strength to 7.5 cN/dtex or less, product quality is improved by suppressing thread breakage and fluff generation during high-level processing processes. Preferably, it is 6.4 to 6.9 cN/dtex.

The polyamide multifilament, which is an embodiment of the present invention, preferably has a tensile strength of 9.5 cN/dtex or more. When the tensile strength is 9.5 cN/dtex or more, the durability of the lace becomes good, thread breakage in high-order processing processes is small, and high-order passability becomes good. It is more preferable that the polyamide multifilament, which is an embodiment of the present invention, has a tensile strength of 10.0 cN/dtex or more. In addition, the larger the tensile strength, the more desirable it is, but its upper limit in the present invention is about 11.5 cN/dtex.

The polyamide multifilament of one embodiment of the present invention preferably has a total fineness of 20 to 44 dtex. By setting it within this range, a lace knitted fabric with a beautifully shiny pattern, excellent feel, and good durability is obtained. By keeping the total fineness below 44dtex, the transparency of the lace yarn increases, making the pattern shine beautifully and creating a lace knit that is soft to the touch. By setting the total fineness to 20 dtex or more, the strength and nodule strength become sufficient, and the durability of the lace becomes good. More preferably, it is 22 to 33 dtex.

The polyamide multifilament of one embodiment of the present invention preferably has a fineness variation value (U%), which is an indicator of thickness unevenness in the fiber longitudinal direction, of 1.2% or less. By setting this range, there will be no uneven dyeing or lines due to the condition of the multifilament after dyeing the lace knitted fabric, and the product quality will be good. More preferably, it is 1.0% or less. In addition, the smaller the U%, the more preferable it is, but the lower limit in the present invention is about 0.4%.

The cross-sectional shape of the polyamide multifilament according to one embodiment of the present invention is not particularly limited. For example, it may be a round cross-section, a flat cross-section, a lenticular cross-section, a trefoil cross-section, a multi-lobal cross-section, a heterogeneous cross-section with 3 to 8 convex portions and an equal number of concave portions, a hollow cross-section, and other known irregular cross-sections.

The present invention further provides a method for producing the polyamide multifilament. The method for producing polyamide multifilament of the present invention includes the steps of melting a polyamide resin, cooling and solidifying each filament discharged from a spinneret, and stretching.

The method includes (1) a spinneret for discharging the molten polyamide resin and forming a filament, (2) passing the filament through heating, (3) a cooling device for cooling and solidifying the filament, and (4) ) A polyamide multi-processor comprising at least a fluid swirling nozzle device for imparting convergence to the yarn by swirling flow, (5) a pulling roller for taking and stretching the filament, and (6) a stretching device for stretching the filament. This is carried out using a filament manufacturing device.

Additionally, the method is characterized by simultaneously satisfying the following conditions (A) to (D).

(A) The heating bowl is installed on the top of the cooling device.

(B) The fluid swirling nozzle device is installed on the top of the receiving roller.

(C) The stretching device is a multi-stage stretching device with two or more stages.

(D) Low-relaxation heat treatment immediately after multi-step stretching

An example of a method for producing polyamide multifilament, which is an embodiment of the present invention, will be described in detail below. Figure 1 shows one embodiment of a manufacturing apparatus that can be preferably used for manufacturing polyamide multifilament, which is one embodiment of the present invention.

The polyamide multifilament, which is an embodiment of the present invention, melts the polyamide resin, meters and transports the polyamide polymer by a gear pump, and is finally extruded from the discharge hole formed in the spinneret 1 to form each filament. do. In this way, as shown in FIG. 1, each filament discharged from the spinneret 1 is heated so as to spread around the entire circumference in order to slowly cool the gas supply device 2 that ejects steam to suppress contamination of the spinneret over time. A container 3 is installed, and the yarn is cooled and solidified to room temperature in a cooling device 4. Afterwards, an emulsion is applied by the oil supply device 5, and each filament is collected to form a multifilament, and intertwined by the fluid turning nozzle device 6, and the receiving roller 7, the first stretching roller 8, It is stretched in two stages on the second stretching roller (9) and relaxed on the relax roller (10). The loose yarn is entangled by the entanglement imparting device 11 and wound by the winding device 12.

In the production of polyamide multifilament, which is one embodiment of the present invention, the relative viscosity of the polyamide resin in sulfuric acid is preferably 2.5 to 4.0. By setting this range, polyamide multifilament with high strength, nodule strength, and high tensile strength can be obtained.

Additionally, the melting temperature is preferably higher than 20°C relative to the melting point (Tm) of the polyamide and lower than 95°C relative to Tm.

In the production of polyamide multifilament, which is an embodiment of the present invention, a heating tube 3 is installed at the top of the cooling device 4 to surround each filament around the entire circumference. By installing the heating tube (3) above the cooling device (4) and keeping the ambient temperature within the heating tube within the range of 100 to 300°C, the polyamide polymer discharged from the spinneret (1) suffers little thermal deterioration and has good orientation. It can be alleviated. By relaxing the orientation through slow cooling from the spindle surface to cooling, multifilament with high strength, 15% strength, and high tensile strength is obtained. If a heating tube is not installed, it is difficult to obtain fibers that satisfy all of the strength, 15% strength, and tensile strength due to insufficient orientation relaxation by slow cooling from the spindle surface to cooling.

In the production of polyamide multifilament, which is one embodiment of the present invention, it is preferable that the heating tube is multilayered. In medical fine fineness and single yarn fineness areas such as polyamide multifilament, which is an embodiment of the present invention, if the temperature distribution in the heating tank is constant, thermal convection is likely to be disturbed, affecting the solidification state of each filament. It becomes a factor that worsens U%. Therefore, by making the heating tube multi-layered and lowering the temperature setting step by step from the upper layer to the lower layer, heat convection is intentionally created from the upper layer to the lower layer, and by creating a descending airflow in the same direction as the accompanying flow of the yarn, By suppressing the disturbance of thermal convection, a multifilament with less yarn shaking and a lower U% is obtained.

The length (L) of the multilayer heating tube also depends on the fineness of the filament, but is preferably 40 to 100 mm. In addition, the multi-layer heating tube is preferably composed of two or more layers, and the single-layer length (L1) of the multi-layer heating tube is preferably in the range of 10 to 25 mm.

In addition, it is preferable that the ambient temperature within the multi-layer heating tube forms a gentle temperature gradient between each layer within the range of 100 to 300°C. For example, when the multi-layer heating tube length (L) is 75 mm and the single-layer length (L1) is 25 mm, the heating tube has a three-layer structure, with the atmospheric temperature of the upper layer being 250 to 300°C and the atmospheric temperature of the middle layer being 250 to 300°C. The temperature of the atmosphere in the lower layer is 200 to 250°C and 100 to 200°C.

With this configuration, the atmospheric temperature profile between the spinneret and cooling is controlled in stages from 100 to 300°C, and polyamide multifilament with high strength, appropriate 15% strength, high tensile strength, and good U% can be obtained.

In the production of polyamide multifilament, which is an embodiment of the present invention, the cooling device 4 is a cooling device that blows out cooling, rectified wind from a certain direction, or an annular cooling device that blows out cooling, rectified wind from the outer periphery toward the center. It can be manufactured using any method, such as a device or an annular cooling device that blows cooling rectified wind from the center toward the outer periphery.

The vertical distance (LS) (hereinafter referred to as cooling start distance (LS)) from the lower surface of the spinneret to the upper end of the cooling wind blowing part of the cooling device (4) is in the range of 159 to 219 mm to prevent yarn shake or U%. It is preferable in that it suppresses, and 169 to 189 mm is more preferable. Regarding the cooling wind speed emitted from the cooling air blowing surface, it is preferable that the average of the section from the upper surface of the cooling blowing part to the lower surface is in the range of 20.0 to 40.0 m/min in terms of strength, elongation, U%, etc. do.

In the production of polyamide multifilament, which is one embodiment of the present invention, the position of the oil supply device 5, that is, the vertical distance (Lg) from the lower surface of the spinneret in FIG. 1 to the oil supply nozzle position of the oil supply device 5 ) (hereinafter referred to as the oil supply position Lg) depends on the single yarn fineness and the cooling efficiency of the filament from the cooling device, but is preferably 800 to 1500 mm, more preferably 1000 to 1300 mm.

In the case of 800 mm or more, the filament temperature is lowered to an appropriate level when applying the oil agent, and in the case of 1500 mm or less, yarn shaking due to descending air currents is small, and a multifilament with a low U% is obtained. In addition, in the case of 1500 mm or less, the distance from the solidification point to the oil supply position is shortened, thereby reducing the entrained flow, the spinning tension is lowered, thereby suppressing the spinning orientation, and the stretchability is excellent, so the strength, elongation, and strength points of 15% It is desirable in In the case of 800 mm or more, the bending of the yarn from the feeder to the oiling guide becomes appropriate, and it is less susceptible to abrasion on the guide, so the strength reduction by 15% is reduced.

In the production of polyamide multifilament, which is one embodiment of the present invention, a fluid turning nozzle device (6) is installed on the upper part of the receiving roller (7). In Patent Document 1, it is proposed that stretching is performed while performing a entanglement treatment during stretching. This is effective in the single yarn fineness range for industrial use, but in the medical fine fineness and single yarn fineness ranges such as polyamide multifilament, which is an embodiment of the present invention, entanglement of the single yarns is likely to occur when entangled during stretching. Additionally, the creation of interwoven points reduces the stretchability of the yarn at the interwoven points during stretching under high tension, and causes stress to concentrate in parts other than the interwoven points. As a result, the strength decreases and fluff becomes easy to occur. Therefore, by applying a fluid swirling nozzle before stretching and providing appropriate convergence properties to the yarn without entangled points, uniform stretching is performed, and polyamide multifilament with high strength and no fluff is obtained.

The fluid swirl nozzle has a shape as shown in Fig. 4, and convergence properties are imparted to the yarn by swirling flow from one direction within the cylinder. The length (LA) of the turning nozzle also depends on the fineness of the filament, but is preferably 5 to 50 mm from the viewpoint of providing convergence properties.

Additionally, it is preferable that the blowing pressure of the swirling flow is 0.05 to 0.20 MPa. By setting the blowing pressure in this range, appropriate convergence properties can be imparted to the filament, and there is no decrease in stretchability during stretching under high tension, and single yarn disorganization does not occur during stretching, so fluff can be achieved even with finer or finer single yarns. A high-strength polyamide multifilament without lint is obtained.

In the production of polyamide multifilament, which is an embodiment of the present invention, stretching is performed in two or more stages. In the case of single-step drawing, when drawing is performed at a high magnification and it is desired to obtain yarn with high fiber modulus and high strength, the drawing tension increases and the draw point is located on the taking roller, which worsens the drawability and reduces the strength. , fluff becomes more likely to occur. By multi-stage stretching of two or more stages, the load on the yarn that acts during stretching is distributed, and the draw point is stabilized between rollers, so stretching is stable, and high strength and high fiber modulus provide an appropriate 15% strength and no fluff. A free polyamide multifilament is obtained.

The total stretch ratio is preferably 3.5 to 5.0 times, and more preferably 3.8 to 4.7 times, in order to achieve the stretch range specified in the present invention. Additionally, the draw ratio of the first stage is preferably 2.5 to 3.5 times, and more preferably 2.7 to 3.3 times. Additionally, during stretching, the receiving roller 7 is heated to 40 to 60°C, the first stretching roller 8 is heated to 130 to 170°C, and the second stretching roller 9 is heated to 150 to 200°C (heat setting temperature). Additionally, the speed of the receiving roller 7 is preferably 500 to 1,300 m/min, and more preferably 700 to 1,100 m/min.

In the production of polyamide multifilament, which is an embodiment of the present invention, the relaxation rate of the stretching roller 9 and the relaxation roller 10 [(stretching roller speed - relax roller speed) / (relax roller speed) × 100] It is preferable to set it to 0 to 1.5%. By setting this range, the relaxation rate is lower than when producing general polyamide multifilament, and heat setting is performed with less relaxation (low-relaxation heat treatment), which improves the linearity of the molecular chain and reduces the amorphous content inside the fiber. A structure in which the parts are uniform and appropriately protruded is obtained, and polyamide multifilament with high strength, high nodule strength, and high tensile strength is obtained. If the relaxation rate is greater than 1.5%, heat setting is performed in a state of high relaxation, so the linearity of the molecular chain decreases, and the strength and nodule strength decrease.

For example, by adopting the conditions of the direct spinning stretching method as shown in FIG. 1 described above, polyamide with a single yarn fineness of 0.8 to 7 dtex, high strength of 7.5 to 8.5 cN/dtex, and high nodule strength of 6.0 to 7.5 cN/dtex. Multifilaments are obtained.

The polyamide multifilament, which is one embodiment of the present invention, is supplied as raw yarn to a lace knitting machine as a branch yarn and knitted into lace paper by a conventional method. The lace paper can be made of ordinary knitted structures such as embroidery lace, Raschel lace, and river lace.

In addition, dyeing after knitting, subsequent post-processing, and final setting conditions may be performed according to known methods. As dyes, acid dyes and reactive dyes may be used, and the colors, etc., are not limited.

Example

Hereinafter, the present invention will be described in more detail through examples.

A. Robber, believer, strong believer, 15% strength

Measure fiber samples according to JIS L1013 (2010) tensile strength and elongation, and draw a tensile strength-elongation curve. As test conditions, the type of test machine was constant speed extension type, grip spacing was 50 cm, and tensile speed was 50 cm/min. In addition, when the tensile strength at the time of cutting was smaller than the maximum strength, the maximum tensile strength and elongation at that time were measured.

Robbery and gangsterism were calculated using the following formula.

Elongation = Elongation at cutting (%)

Strength = tensile strength at cutting (cN) / total fineness (dtex)

Strong thief = {strength (cN/dtex)}×{strength (%)+100}/100

15% strength = tensile strength at 15% elongation (cN) / total fineness (dtex)

B. Nodule strength

In accordance with the JIS L-1013 (2010) nodule strength, a nodule was created in the center between the grips of the sample and measured under the same conditions as the strength and elongation measurements above.

Nodule strength was determined by the following equation.

Nodule strength = tensile strength when cut (cN) / total fineness (dtex)

C．Total fineness, single yarn fineness

Set the fiber sample on a 1.125m/circumference measuring machine, rotate it 500 times to produce a loop-shaped skein, dry it with a hot air dryer (105 ± 2°C x 60 minutes), measure the mass of the skein using a balance, and determine the process moisture content. The fineness was calculated from the multiplied value. Additionally, the process moisture content was set to 4.5%.

D. Sulfuric acid relative viscosity (ηr)

0.25 g of the polyamide chip sample was dissolved to 1 g in 100 ml of sulfuric acid with a concentration of 98% by mass, and the flow time (T1) at 25 degrees was measured using an Oswald viscometer. Subsequently, the flow time (T2) of only sulfuric acid with a concentration of 98% by mass was measured. The ratio of T1 to T2, that is, T1/T2, was taken as the relative viscosity of sulfuric acid.

E．U%

Using USTER TESTER IV manufactured by Zellweger Uster, the fiber sample was measured with sample length: 500 m, measuring yarn speed V: 100 m/min, Twister (number of rotations): S twist, 30000/min, and 1/2 Inert.

F. Number of fluff

The obtained fiber sample was rewound at a speed of 500 m/min, a laser-type fluff detector was installed at a location 2 mm away from the yarn during rewound, and the total number of detected defects was converted to the number per 100,000 m and displayed.

G．Race Evaluation

(a) Softness

For lace products, the softness was evaluated by five testers (five people) with extensive experience in tactile evaluation, based on a lace knitted fabric manufactured by the same method as Example 1 using 40 dtex, 4-filament nylon 6 multifilament. So I evaluated it relative to others. The results were obtained by taking the average of each tester's evaluation points, rounding off decimals, and making the average value ◎ for 5, 0 for 4, △ for 3, and × for 1 to 2.

5 points: Very good

4 points: slightly excellent

3 points: average

2 points: slightly behind

1 point: falling behind

◎ and ○ were considered as passing softness.

(b) Durability

The bursting strength was measured at three arbitrary points in accordance with JIS L1096 (2010) and the bursting strength test method by the Muren method (Method A), and was evaluated in 4 levels based on the following criteria from the average value.

◎: 150kPa or more

○: 120 kPa or more and less than 150 kPa

△: 110kPa or more and less than 120kPa

×: Less than 110kPa

◎ and ○ were considered durability passes.

(c) Product quality (fluff)

Number of pillings in lace fabric: The number of pilling parts (a state in which the fibers on the surface of the knitted fabric are fluffed and the fluff is entangled with each other, generating a small spherical lump) per sheet of lace fabric is indicated according to the following criteria. did.

◎: 0 or more but less than 2

○: 2 or more but less than 5

△: 5 or more but less than 10

×: 10 or more

◎ and ○ were considered acceptable.

(d) Process passability

Knitting operation efficiency: The number of single yarns during knitting was expressed as the number of single yarns per 1 sheet (80 m) of lace dough, using the following criteria.

◎: 0 or more but less than 5 cases

○: 5 or more but less than 10 cases

△: 10 or more but less than 20 cases

×: 20 or more but less than 30 cases

◎ and ○ were taken as passing the process.

(e) Elegance (state of brilliance of the pattern)

The products were evaluated relative to the degree of brilliance of the pattern by five testers. The results were obtained by taking the average of each tester's evaluation points, rounding off decimals, and making the average value ◎ for 5, ○ for 4, △ for 3, and × for 1 to 2.

5 points: Very good

4 points: slightly excellent

3 points: average

2 points: slightly behind

1 point: falling behind

◎ and ○ were considered acceptable.

[Example 1]

(Manufacture of polyamide multifilament)

As polyamide, nylon 6 (N6) chips with a sulfuric acid relative viscosity (ηr) of 3.3 and a melting point of 225°C were dried by a conventional method to a moisture content of 0.03% by mass or less. The obtained nylon 6 chips were melted at a spinning temperature (melting temperature) of 298°C and discharged from the spinneret (discharge amount: 38.6 g/min). The spinneret had an odd number of 20, was round, had a hole diameter (ϕ) of 0.25, and had 4 threads per spinneret.

Radiation was performed using an radiator of the type shown in FIG. 1. In addition, the heating tube uses a two-layer heating tube with a heating tube length (L) of 50 mm and a single-layer length (L1, L2) of 25 mm each, and the atmospheric temperature of the upper layer heating tube is 300°C, and the atmospheric temperature of the lower layer heating tube is 300°C. The temperature was set to 150°C. Each filament discharged from the spinneret is slowly cooled at an ambient temperature of 150 to 300°C in a two-layer heating tube and passed through a cooling device (4) with a cooling start distance (LS) of 169 mm, a wind temperature of 18°C, and a wind speed of 35 m/min. The thread was cooled and solidified to room temperature. After that, the oil supply position (Lg) from the spinneret surface is applied at a position of 1300 mm, and each filament is converged to form a multifilament, and the fluid swirling nozzle device 6 with a swirling nozzle length (LA) of 25 mm Water properties were granted. Convergence properties were imparted by spraying high-pressure air from the direction of the arrow onto the running yarn within the fluid swirling nozzle device 6. The pressure of the air being sprayed was 0.1 MPa (flow rate 15 L/min). After that, the first stage is stretched so that the stretching ratio between the receiving roller 7 and the first stretching roller 8 is 2.9 times, and then the stretching ratio is increased between the first stretching roller 8 and the second stretching roller 9. The second stage of stretching was carried out to increase the size by 1.5 times. Subsequently, 1.0% relaxation was performed between the second stretching roller 9 and the relaxation roller 10, the yarn was entangled in the entanglement imparting device 11, and then wound by the winding device 12. At this time, the overall stretching ratio expressed by the take-up speed and stretching speed ratio was adjusted to be 4.35 times. The surface temperature of each roller was set to 40°C for the receiving roller, 150°C for the first stretching roller, and 185°C for the second stretching roller, and the relax roller was set to room temperature. The entanglement treatment was performed by spraying high-pressure air from a direction perpendicular to the running yarn within the entanglement imparting device. The pressure of the spraying air was 0.2 MPa. In this way, 33 dtex, 5 filament nylon 6 multifilament was obtained.

The results of evaluating the obtained nylon 6 multifilament are shown in Table 1.

(Manufacture of lace knitted fabric)

Next, the above-described multifilament was warped and knitted with a runner length of 21.0 cm as a back side yarn of 28G Russell lace branch, and a runner length of 100.0 cm and a thread of 235 to 330 dtex as a front side yarn of the branch yarn. Next, lace knitted fabric for inner use was obtained by scouring, dyeing, and finishing setting the fabric. The results of evaluating the obtained lace products are shown in Table 1.

[Example 2]

33dtex, 5-filament nylon 6 multifilament was fabricated in the same manner as in Example 1, except that the relaxation rate between the second stretching roller 9 and the relaxation roller 10 was set to 0% and the strength and nodule strength were changed. and obtained lace knitted fabric. The evaluation results are shown in Table 1.

[Example 3]

33dtex, 5-filament nylon 6 multifilament was fabricated in the same manner as in Example 1, except that the relaxation rate between the second stretching roller 9 and the relaxation roller 10 was set to 1.5% and the strength and nodule strength were changed. and obtained lace knitted fabric. The evaluation results are shown in Table 1.

[Example 4]

As polyamide, 33 dtex, 5 filament nylon 66 multifilaments were obtained in the same manner as in Example 1, except that nylon 66 (N66) chips with a sulfuric acid relative viscosity (ηr) of 3.2 and a melting point of 265°C were used, and a lace knit fabric was obtained. got it The evaluation results are shown in Table 1.

[Comparative Example 1]

Nylon 6 with 33 dtex and 5 filaments was fabricated in the same manner as in Example 1 except that the relaxation rate between the second stretching roller 9 and the relaxation roller 10 was set to 2.0% and the nodule strength was set to 5.9 cN/dtex. I got multifilament, and I got lace knitting. The evaluation results are shown in Table 1.

Since the relaxation rate was 2.0%, heat setting was performed in a state of large relaxation, which lowered the linearity of the molecular chain and lowered the nodule strength. Because of this, the durability of lace knitwear was inferior.

[Example 5]

Nylon 6 multifilament of 22 dtex and 7 filaments was obtained in the same manner as in Example 1, except that the discharge rate was 38.6 g/min, the odd number of spinnerets was 42, and 6 yarns per spinneret were used, and a lace knitted fabric was obtained. The evaluation results are shown in Table 2. The durability of the lace knitted fabric was good, it could maintain durability even if the fineness was increased, and it had a soft feel. Additionally, as the fineness increased, the transparency of the lace fibers increased, and the pattern shined more beautifully than in Example 1.

[Example 6]

Nylon 6 multifilament of 22 dtex and 20 filaments was produced in the same manner as in Example 1 except that the discharge rate was 25.8 g/min, the odd number of spinnerets was 80, the hole diameter (ϕ) was 0.18, and 4 threads/bunnel were used. I got it, and I got the lace knitted fabric. The evaluation results are shown in Table 2. The durability of the lace knitted fabric was good, the durability could be maintained even if the fineness was increased, and it had a very soft feel. Additionally, as the fineness increased, the transparency of the lace fibers increased, and the pattern shined more beautifully than in Example 1.

[Example 7]

A nylon 6 multifilament of 42 dtex and 6 filaments was obtained by the same method as Example 1 except that the discharge rate was 49.2 g/min, the odd number of spinnerets was 24, the hole diameter (ϕ) was 0.30, and 4 yarns per spinneret were used. , obtained lace knitted fabric. The evaluation results are shown in Table 2. The durability of the lace knitted fabric was good and it had a soft feel. In addition, because the U% was very good, it was a lace knitted fabric with less uneven dyeing than Example 1.

[Comparative Example 2]

Nylon 6 multifilament of 33 dtex and 5 filaments was obtained in the same manner as in Example 1, except that the fluid swirling nozzle device 6 was not provided, and a lace knitted fabric was obtained. The evaluation results are shown in Table 2.

In the medical fineness and single yarn fineness ranges, the single yarn fineness is thin, so when braided during drawing, the single yarn becomes entangled, the stretchability of the yarn at the braided point decreases, strength decreases, and fluff occurs. . As a result, the process passability, durability, and product quality (fluff) of lace knits were inferior.

[Comparative Example 3]

The method was the same as in Example 1, except that the fluid swirling nozzle device 6 was not installed, the discharge rate was 43.9 g/min, the odd number of spinnerets was 5, the hole diameter (ϕ) was 0.50, and 1 yarn per spinneret was used. By doing this, 150 dtex, 5 filament nylon 6 multifilament was obtained, and a lace knitted fabric was obtained. The evaluation results are shown in Table 2.

Because the fineness and single yarn fineness were large, the softness of the lace knitted fabric was inferior. Additionally, because the fineness of the thread was too thick, the lace thread did not have the transparency and the pattern did not shine beautifully.

[Comparative Example 4]

Nylon 6 multifilament of 22 dtex and 32 filaments was obtained by the same method as Example 1 except that the discharge rate was 19.3 g/min, the odd number of spinnerets was 96, the hole diameter (ϕ) was 0.16, and 3 yarns/bunnel were used. , obtained lace knitted fabric. The evaluation results are shown in Table 2.

Compared to Examples 5 and 6, the single yarn fineness is thinner, so the feel is improved, but the polyamide fibers are rapidly cooled in the cooling section, and the stretchability decreases, strength and nodule strength decrease, U% deteriorates, and fluff also decreases. increased. As a result, the process passability, durability, and product quality (fluffing and unevenness) of lace knits were inferior.

[Comparative Example 5]

As shown in Fig. 2, without providing the second stretching roller 9 and the relax roller 10, the taking roller 7 and the first stretching roller 8 are (8) The same method as Example 1 except that only one stage was stretched so that the stretching ratio between the first stretching rollers (8) and the winding device (12) was stretched at a relaxation rate of 1.0%. 33dtex, 5-filament nylon 6 multifilament was obtained, and a lace knitted fabric was obtained. The evaluation results are shown in Table 2.

Because the stretching was performed at a high magnification by single-stage stretching, the stretching properties deteriorated, the strength decreased, and fluff occurred. As a result, the process passability, product quality (fluff), and durability of lace knits were inferior.

[Comparative Example 6]

As shown in Fig. 2, without providing the second stretching roller 9 and the relaxation roller 10, the taking roller 7 and the first stretching roller 8 are used to The same method as in Example 1 except that only one stage was stretched so that the stretching ratio between the rollers 8 was 4.35 times, and the stretching was relaxed at a relaxation rate of 5.0% between the first stretching roller 8 and the winding device 12. By the same method, nylon 6 multifilament of 33dtex and 5 filaments was obtained, and a lace knitted fabric was obtained. The evaluation results are shown in Table 2.

Because the stretching was performed at a high magnification by single-stage stretching, the stretching properties deteriorated, the strength decreased, and fluff occurred. Additionally, because the relaxation rate was 5.0%, heat setting was performed in a state of large relaxation, which lowered the linearity of the molecular chain and lowered the nodule strength. As a result, the process passability, quality, and durability of lace knits were inferior.

Although the present invention has been described in detail using specific forms, it is clear to those skilled in the art that various changes and modifications can be made without departing from the intent and scope of the present invention. In addition, this application is based on the Japanese patent application (Japanese patent application 2018-10324) filed on January 25, 2018, and is incorporated by reference in its entirety.

1: Spinneret 2: Gas supply device
3: heating tank 4: cooling device
5: Oil supply device 6: Fluid swirling nozzle device
7: Taking roller 8: First stretching roller
9: Second stretching roller 10: Relax roller
11: Bridging device 12: Winding device
L: Length of multi-layer heating tube L1: Length of single layer of multi-layer heating tube
LS: Cooling start distance Lg: Lubrication position
LA: Swirling nozzle length

Claims (6)

Polyamide multifilament characterized by a single yarn fineness of 0.8 to 7 dtex, a strength of 7.5 to 8.5 cN/dtex, and a nodule strength of 6.0 to 7.5 cN/dtex. According to claim 1,
A polyamide multifilament characterized by a tensile strength of 6.1 to 7.5 cN/dtex at 15% elongation. The method of claim 1 or 2,
Polyamide multifilament characterized by a total fineness of 20 to 44 dtex. A lace knitted fabric using the polyamide multifilament according to claim 1 or 2 as a lace yarn. delete delete