KR102363120B1 - Polyamide multifilament and lace knitting and stockings using same - Google Patents

Abstract

A polyamide multifilament, characterized in that the tensile strength at 15% elongation is 4.0 to 6.0 cN/dtex, the tensile strength is 10.0 cN/dtex or more, and the yarn unevenness (U%) is 1.2 or less. We provide stockings with excellent softness, durability and transparency, and high-strength polyamide multifilaments with excellent durability and finely shiny lace knitting.

Description

Polyamide multifilament and lace knitting and stockings using same

The present invention relates to polyamide multifilaments. More specifically, when the polyamide multifilament of the present invention is used in stockings, it provides a stocking with excellent softness, durability, and transparency, and when used in the base thread of lace paper, it has excellent durability and a lace with a fine pattern It relates to polyamide multifilaments capable of providing a knitted fabric.

Polyamide fibers and polyester fibers, which are synthetic fibers, are widely used in medical and industrial applications because they have excellent properties in mechanical and chemical properties. In particular, polyamide fibers are widely used in general medical applications such as stockings, inner wear, sports wear, etc. because they have excellent properties in their unique softness, high strength, color development during dyeing, heat resistance, hygroscopicity, and the like.

As a consumer demand for lace, in order to make the pattern shiny, durability was the same as before, and the transparency of the lace base thread was desired. As a consumer demand for stockings, in order to provide a good fit and feel of bare skin, the durability remains the same as before, and the pursuit of softness and transparency was desired. That is, when it is substituted with medical polyamide fibers, it has been strongly desired for the strength to be reduced to the same fineness as in the prior art.

In order to solve these problems, various techniques have been proposed for increasing the strength of polyamide fibers. For example, in Patent Document 1, a lace knitted fabric made of high-viscosity type nylon 6 filaments having an elongation of 51 to 64% and a strength of 4.2 to 6.5 cN/dtex is proposed.

Patent Document 2 proposes a stocking made of a polyamide filament having an elongation of 40 to 50%, a strength-elongation product of 9.1 cN/dtex or more, and about 9.8 cN/dtex.

Patent Document 3 proposes a tire cord and a belt made of polyamide fibers having an elongation of about 16 to 18%, a strength of 9.8 cN/dtex or more, and an elongation of about 11.4 to 12.2 cN/dtex.

Japanese Patent Laid-Open No. 2003-129331 International Publication No. 2016/76184 Japanese Patent Laid-Open No. 63-159521

However, in the method described in Patent Document 1, although a lace with a fine pattern was obtained, the fiber modulus and the elongation were low, and the product strength of the lace knitted fabric was not satisfactory.

When the method described in Patent Document 2 was developed and used to a fineness suitable for the coated yarn of the single covering elastic yarn, the fiber modulus and the elongation were low, and the product strength of the stocking was not satisfactory.

When the method described in Patent Document 3 was developed and used for medical purposes, the fiber modulus was too high and the high-order passageability such as yarn breakage and fluff generation in the manufacturing process of laces or stockings was inferior.

The present invention solves the above problems, and an object of the present invention is to provide a high-strength polyamide multifilament having high elongation and an appropriate fiber modulus. More specifically, the high-strength and high-strength polyamide multifilaments with appropriate fiber modulus have excellent high-order pass-through and product quality, enable finer fineness, and increase the transparency of the lace-based thread while maintaining durability. An object of the present invention is to provide a stocking knitted with lace and having excellent transparency and softness.

In order to solve the said subject, this invention employ|adopts the following structures.

(1) A polyamide multifilament characterized in that the tensile strength at 15% elongation is 4.0 to 6.0 cN/dtex, the tensile strength is 10.0 cN/dtex or more, and the yarn unevenness (U%) is 1.2 or less.

(2) The polyamide multifilament according to (1) above, wherein the single yarn fineness is 1.3 to 3.4 dtex.

(3) The polyamide multifilament according to (1) or (2), wherein the elongation is 30 to 50%.

(4) The polyamide multifilament according to any one of (1) to (3), wherein the sum of the crystalline amount and the rigid non-quantitative amount is 70 to 90%.

(5) A lace knitted fabric using the polyamide multifilaments according to any one of (1) to (4) for a lace base yarn.

(6) A stocking in which the polyamide multifilament according to any one of (1) to (4) is used as a covering covering yarn, and the covering yarn is partially used.

(Effects of the Invention)

The polyamide multifilament of the present invention is a high tenacity polyamide multifilament having high elongation and an appropriate fiber modulus. In addition, the polyamide multifilament of the present invention has excellent high-order passability and product quality, can be made finer, and the transparency of the lace base thread is increased while maintaining durability. You can get the stockings you have.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows one embodiment of a manufacturing apparatus that can be suitably used in the method for manufacturing a polyamide multifilament of the present invention.
Fig. 2 is a schematic cross-sectional model view showing a spinneret and a heating tube that can be preferably used in the method for producing a polyamide multifilament of the present invention.

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

The polyamide multifilament of the present invention is characterized in that the tensile strength at 15% elongation is 4.0 to 6.0 cN/dtex, the tensile strength is 10.0 cN/dtex or more, and the yarn unevenness (U%) is 1.2 or less.

The polyamide constituting the polyamide multifilament of the present invention is a resin composed of a high molecular weight body in which a so-called hydrocarbon group is connected to the main chain through an amide bond. ), polyhexamethylene adipamide (nylon 66) is preferable, and polycaproamide (nylon 6) is more preferable from the viewpoint of less gelation and good spinning properties. “Mainly” in the above description means that in polycaproamide, ε-caprolactam constituting polycaproamide is a constituent unit, and in polyhexamethylene adipamide, hexamethylenediammonium adipate constituting polyhexamethylene adipamide is used. of 80 mol% or more as a structural unit, and more preferably 90 mol% or more. Although it does not specifically limit as another component, For example, polydodecanoamide, polyhexamethylene adipamide, polyhexamethylene azellamide, polyhexamethylene sebacamide, polyhexamethylene dodecanoamide, polymethxylylene adipamide and units such as aminocarboxylic acid, dicarboxylic acid, and diamine which are monomers constituting mide, polyhexamethylene terephthalamide, polyhexamethylene isophthalamide, and the like.

In addition, in order to effectively express the effects of the present invention, the polyamide preferably does not contain various additives such as a gloss remover typified by titanium oxide. good to be In addition, the content may be mixed as needed between 0.001-0.1 wt%.

The polyamide multifilament of the present invention needs to have 15% strength, elongation, and U% as a whole within these ranges. That is, by increasing the fineness of the lace base thread, the transparency of the lace base thread is increased to obtain a lace knitted fabric with a finely shiny pattern or stockings having excellent transparency and softness, but the product strength is lowered and the durability is at a level that cannot withstand actual use. In order to set the durability to a level that can withstand actual use, it is necessary to increase the strength and strength. In addition, in order to maintain high passability and product quality, it is necessary to set it to an appropriate 15% strength and U%.

Therefore, the present inventors carefully studied, to provide a high-order passability and excellent product quality, excellent durability, and increased transparency of the lace ground thread to provide a finely shiny lace knitted fabric or stocking with excellent transparency and softness. It has been found that it is essential to set strength, stretchability, and U% as appropriate domains.

The polyamide multifilament of the present invention needs to have a tensile strength of 10.0 cN/dtex or more. By setting it as such a range, the durability of a stocking and a race becomes a level which can withstand actual use. When the tensile strength is less than 10.0 cN/dtex, the durability of stockings or laces is at a level that cannot withstand actual use, and the yarn breakage in the high-order processing step increases, and the high-order passability deteriorates. More preferably, the polyamide multifilament of the present invention has a tensile strength of 10.3 cN/dtex or more. Moreover, although it is so preferable that the tensile strength is large, the upper limit in this invention is about 11.0 cN/dtex.

The polyamide multifilament of the present invention needs to have a tensile strength at 15% elongation (hereinafter referred to as “15% strength”), which is one of the index of yarn physical properties, of 4.0 to 6.0 cN/dtex. The 15% strength is measured according to JIS L1013-2010-tensile strength and elongation, and a tensile strength-elongation curve is drawn, and the value obtained by dividing the tensile strength (cN) at 15% elongation by the fineness is 15% strength. The 15% strength is a value that simply represents the fiber modulus. When the 15% strength is high, the gradient of the tensile strength-elongation curve is high, indicating that the fiber modulus is high. On the other hand, when the 15% strength is low, the gradient of the tensile strength-elongation curve is low, indicating a low fiber modulus.

By setting the polyamide multifilament of the present invention within this range, the durability of stockings or lace knitted fabrics is at a level that can withstand actual use, and the softness is also excellent. If the 15% strength is less than 4.0 cN/dtex, the tensile strength is lowered and the durability of the stocking or lace knitted fabric is at a level that cannot withstand actual use. When the 15% strength exceeds 6.0 cN/dtex, the elongation decreases, the softness of the stockings or lace knitted fabric becomes hard to the touch, and the softness deteriorates. is lowered Preferably it is 4.5-5.5 cN/dtex.

The polyamide multifilament of the present invention preferably has an elongation of 30 to 50%. By setting it as such a range, yarn breakage in a high-order processing process decreases, and high-order passability and product quality become favorable. In particular, when knitting and weaving at high speed, it is excellent in high-order passability. When the elongation is 30% or more, there is less yarn breakage in a high-order processing process such as a stocking manufacturing process (a covering company manufacturing process or a stocking knitting process) or a lace knitting manufacturing process (a knitting process, a knitting process), and the high-order passability is good. In addition, the soft feel of the stockings or lace knitted fabric is good. If the elongation is 50% or less, the tensile strength is sufficient, and the durability of stockings or lace knitted fabrics can withstand actual use. More preferably, it is 35-45%.

In the polyamide multifilament of the present invention, it is preferable that the sum of the crystalline amount and the rigid non-quantitative amount is 70 to 90%. Crystalline amount and rigidity non-quantitation are values calculated as follows.

The amount of crystallization (Xc) is calculated by Equation (1) by calculating the difference (?Hm-?Hc) between the amount of heat of fusion and heat of cold crystallization by the DSC method. Here, ?Hm0 is the heat of fusion of the crystalline polyamide, and its value is 229.76 J/g.

Incidentally, the rigid non-quantitative amount Xra is calculated by the formula (2) from the crystal amount Xc and the movable non-quantity Xma. The moving specificity (Xma) is calculated from the specific heat change (ΔCp) before and after the glass transition on the temperature-heat flux reversible curve by the temperature modulation DSC method (TMDSC). Here, ΔCp uses the specific heat gap before and after the glass transition calculated by extrapolating the tangent to the temperature-heat flow reversible curve before and after the glass transition. The movable non-quantity Xma is calculated by the formula (3). Here, ΔCp0 is the specific heat difference before and after Tg of the amorphous polyamide, and its value is 0.4745 J/g.

In addition, the stiffness non-quantitation was computed from the average value of two measurements of temperature-modulated DSC and DSC.

Crystalline amount: Xc(%)=(ΔHm-ΔHc)/ΔHm0×100... (1)

Spasticity non-quantitative: Xra(%)=100-(Xc+Xma) ...(2)

Moving non-quantitation: Xma(%)=ΔCp/ΔCp0×100····(3).

The sum of the crystalline amount and the rigid non-quantitative here is a value simply indicating the degree of orientation relaxation of the molecular chains of the polyamide polymer. If the sum of the amount of crystallinity and the stiffness and non-quantitation is high, it indicates that the fiber has high crystallinity due to little deformation of the molecular chain. indicates. When the sum of the crystal amount and the rigidity non-quantitation is 90% or less, the amount of molecular chain deformation of the polyamide polymer becomes appropriate, and a polyamide fiber with not too high crystallinity is obtained, and the feel and softness of stockings or lace knitted fabrics are excellent. do. When the sum of the crystalline amount and the rigidity non-quantitation is 70% or more, the molecular chain of the polyamide polymer is appropriately modified, so that a polyamide fiber with excellent crystallinity is obtained, and the durability of stockings or lace knitted fabrics is excellent. More preferably, it is 75-85%.

The polyamide multifilament of the present invention needs to have a U% of 1.2 or less. By setting it as such a range, it becomes the thing excellent in product quality. If U% exceeds 1.2, after dyeing the lace knitted fabric, the thick part of the thread is dyed heavily, or stripes are generated, etc., resulting in poor appearance and inferior product quality. More preferably, it is 1.0 or less in the case of a stocking use, and 1.0 or less in the case of a lace knitting use. In addition, although it is so preferable that U% is small, the lower limit in this invention is about 0.4.

The total fineness of the polyamide multifilament of the present invention is preferably 4.0 to 33.0 dtex in terms of medical use. For stocking use, 4.0 to 11.0 dtex, and for lace use, 20.0 to 30.0 dtex is more preferable.

The polyamide multifilament of the present invention preferably has a single yarn fineness of 1.3 to 3.4 dtex. By setting it as such a range, it is excellent in the durability and softness of a stocking or a race. More preferably, it is 1.6-3.2 dtex.

The polyamide multifilament of the present invention preferably has a sulfuric acid relative viscosity of 2.5 to 4.0. More preferably, it is 3.2-3.8. By setting the relative viscosity of sulfuric acid to 2.5 to 4.0, the durability of stockings or lace knitted fabrics is at a level that can withstand actual use. In addition, product quality is improved.

The cross-sectional shape of the polyamide multifilament of the present invention is not particularly limited, and includes, for example, a spherical cross-section, a flat cross-section, a lens-shaped cross-section, a trilobular cross-section, a multi-lobal cross-section, and 3 to 8 convex portions and concave portions equal to the number of convex portions. It may be a deformed cross-section having a cross section, a hollow cross-section or other well-known deformed cross-section.

Next, an example of the manufacturing method of the high-strength polyamide multifilament of this invention is demonstrated concretely. 1 shows an embodiment of a manufacturing apparatus by a direct spinning stretching method preferably used in the manufacturing method of the high-strength polyamide multifilament of the present invention.

The polyamide multifilaments of the present invention melt polyamide resin, meter and transport the polyamide polymer with a gear pump, and finally extrude from the discharge hole formed in the spinneret 1 to form each filament. In this way, the gas ejection device 2 for ejecting steam in order to suppress contamination due to aging of the spinneret shown in FIG. It is made to pass through the heating cylinder 3 and the cooling device 4, and a thread is cooled and solidified to room temperature. After that, the oil supply device 5 applies an oil agent, and the filaments are focused to form multifilaments, entangled with the fluid entanglement nozzle device 6, and passed through the take-up roller 7 and the drawing roller 8. , then stretching is performed according to the ratio of the peripheral speeds of the take-up roller 7 and the stretching roller 8 . Moreover, the thread is heat-processed by the heating of the extending|stretching roller 8, and it winds up with the winding-up apparatus 9.

In the production of the polyamide multifilament of the present invention, the relative viscosity of the polyamide resin with sulfuric acid is preferably 2.5 to 4.0. By setting it as such a range, a high-strength polyamide multifilament with high tensile strength is obtained.

Further, the melting temperature is preferably higher than 20°C and lower than 95°C with respect to the melting point of the polyamide.

In the production of the polyamide multifilaments of the present invention, it is necessary that a heating tube 3 is provided in the upper part of the cooling device 4 so as to surround each filament around the entire circumference. By installing a heating tube on the upper part of the cooling device 4 and setting the ambient temperature in the heating tube within the range of 100 to 300 ° C., the polyamide polymer discharged from the spinneret 1 is less thermally deteriorated, and the orientation can be relieved. have. A multifilament with 15% strength and high elongation is obtained by relaxation of orientation by slow cooling from the nozzle surface to the upper surface of the cooling device 4 . If a heating tube is not provided, there is a tendency that it is difficult to obtain fibers satisfying both the strength and elongation of 15% because of insufficient orientation relaxation due to slow cooling from the nozzle surface to the upper surface of the cooling device 4 .

In the production of the high-strength polyamide multifilament of the present invention, it is necessary that the heating tube is multi-layered. In Patent Document 3, a heating tube that maintains the atmospheric temperature just below the nozzle at 250 to 450 ° C. for slow cooling is proposed, but it is effective in the industrial fineness range, but for medical use such as the polyamide multifilament of the present invention. In the fineness region, since the temperature distribution in the heating tube is constant, heat convection tends to be disturbed, and it is a factor that affects the solidification state of each filament and deteriorates U%. For this reason, by making the heating tube multi-layered and gradually lowering the temperature setting from the upper layer to the lower layer, heat convection is intentionally created from the upper layer to the lower layer, and a downdraft flow in the same direction as the accompanying flow of the yarn is made. Convection turbulence is suppressed, yarn fluctuations are small, and multifilaments with a small U% are obtained.

The multilayer heating tube length (L) also depends on the fineness of the filament, but is preferably 40 to 100 mm. Moreover, it is preferable that the multilayer heating cylinder is comprised by two or more layers, and the range of 10-25 mm of single-layer length (L1) of a multilayer heating cylinder is preferable.

Moreover, the atmospheric temperature in a multilayer heating cylinder exists in the range of 100-300 degreeC, WHEREIN: It is necessary to form a gentle temperature gradient between each layer. For example, when the multilayer heating tube length (L) is 75 mm and the single layer length (L1) is 25 mm, the atmospheric temperature of the upper layer is 250-300°C, the atmospheric temperature of the middle layer is 200-250°C, and the atmosphere of the lower layer is It is necessary to set it as the temperature of 100-200 degreeC.

By setting it as such a structure, a high-strength polyamide multifilament with good 15% strength, elongation, and U% is obtained by controlling the atmospheric temperature profile between the nozzle and the upper surface of the cooling device 4 stepwise to 100 to 300°C.

In the production of the polyamide multifilament of the present invention, the cooling device 4 is a cooling device that blows a cooling rectified wind A from a certain direction, or a cooling device that blows a cooling rectified wind A from the outer peripheral side toward the center side. It can be manufactured by any method, such as an annular cooling apparatus or an annular cooling apparatus which blows a cooling rectification wind toward the outer periphery from the center side. The vertical distance LS (hereinafter referred to as the cooling start distance) 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 suppress yarn fluctuation and U% It is preferable at the point to do, and 169-189 mm is more preferable. As for the cooling wind speed blown out from the cooling wind blowing surface, it is preferable to be in the range of 20.0 to 40.0 (m/min) on the average of the section from the upper end to the bottom surface of the cooling blowing unit from the viewpoint of U% and strength. .

In the production of the polyamide multifilament of the present invention, the vertical distance Lg from the position of the oil supply device 5, that is, the lower surface of the spinneret in FIG. 1 to the oil supply nozzle position of the oil supply device 5 (hereinafter, The oil supply position) is preferably 800 to 1500 (mm), more preferably 1000 to 1300 (mm), although it also depends on the single yarn fineness and the cooling efficiency of the filament from the cooling device. In the case of 800 (mm) or more, the filament temperature drops to an appropriate level when applying the emulsion, and in the case of 1500 (mm) or less, the yarn fluctuation due to the downdraft is small, and a multifilament with a low U% is obtained. In addition, in the case of 1500 (mm) or less, as the distance from the solidification point to the oil supply position is shortened, the accompanying flow is reduced, and the radial orientation is suppressed by lowering the spinning tension, so that the ductility is excellent. A high-strength multifilament is obtained. In the case of 800(mm) or more, the yarn bending from the nozzle to the oil supply guide is appropriate, and it is difficult to be affected by abrasion in the guide, so the reduction in strength and strength by 15% is reduced.

In the production of the polyamide multifilament of the present invention, the spinning speed is preferably 1000 to 2000 m/min in the low-speed region of the take-up roller 7, suppressing draft elongation non-uniformity and uniform thread cooling. U% can be suppressed as low as 1.2 or less. In addition, in the case of 2000 m/min or less, while the radial orientation is suppressed and the slow cooling effect of the heating tube is promoted, the strain relaxation of the molecular chain is increased to obtain a high-strength multifilament with high 15% strength and high elongation.

Moreover, it heat-processes the extending|stretching roller 8 as a heating roller, the heat set length is 500-1200 mm, and 120-180 degreeC of heat processing temperature is preferable. This is because it becomes possible to design the heat shrinkage of the multifilament by performing an appropriate heat treatment. When the length of the heat set is 500 mm or more, crystallization of the fibers is sufficient, so the strength is increased by 15%, and a product with excellent durability is obtained. If the length of the heat set is 1200 mm or less, the fiber crystallization does not proceed too much, so the 15% strength is in an appropriate range, the product is soft to the touch, and at the same time, high-strength polyamide multi with excellent process passability in high-order processing. A filament is obtained.

In the polyamide multifilament of the present invention, a heating tube is installed at the top of the cooling device 4, the atmospheric temperature in the heating tube is in the range of 100 to 300° C., and the temperature gradient in the heating tube is made by making the heating tube multi-layered. By intentionally creating a descending airflow in the same direction as the accompanying flow of yarn, set the oil supply position to 800~1500mm from the slit surface, set the spinning speed to 1000~2000m/min, and set the length of the heat set after stretching to 500~1200mm. It can be manufactured by

By adopting the conditions in the direct spinning stretching method, a high tensile strength of 10.0 cN/dtex or more, 15% strength of 4.0 to 6.0 cN/dtex, and high strength polyamide multifilament of 1.2 or less U% can be obtained.

The polyamide multifilament of the present invention is supplied to a lace knitting machine as a blank yarn as it is raw and knitted on lace paper by a conventional method. The lace paper may be a normal knitting organization such as an embroidered lace, a raschel lace, or a river lace.

The polyamide multifilament of the present invention is used as a covering yarn for a covering yarn. The covering yarn uses elastic yarns such as polyurethane-based elastic fibers and polyamide-based elastomer elastic fibers as the core yarn, and is used for single covering yarns in which the covering yarn is wound in one layer, and double covering yarns in which the covering yarns are wound twice.

The polyamide multifilament of the present invention is used for stockings in which the covering yarns described above are partly used. In addition, as the knitting machine of the stocking, a normal socks knitting machine can be used, and there is no limitation, and the knitting machine may be knitted by a conventional method of supplying and knitting the covering yarn of the present invention using a knitting machine of two or four yarn feeders.

In addition, dyeing after knitting, subsequent post-processing, and final set conditions may be performed according to a known method, and an acid dye or a reactive dye is used as the dye, and the color or the like is not limited.

Example

Hereinafter, the present invention will be described in more detail by way of Examples.

A. Strength, Elongation, Elongation, 15% Strength

A fiber sample was measured according to JIS L1013-2010-tensile strength and elongation, and a tensile strength-elongation curve was drawn. As the test conditions, the type of the testing machine was a constant-speed extension type, a grip interval of 50 cm, and a tensile rate of 50 cm/min. In addition, when the tensile strength at the time of cutting|disconnection was smaller than the highest strength, the highest tensile strength and the elongation at that time were measured.

The strength and robbery were calculated by the following formula.

Elongation = Elongation at cut (%)

Strength = tensile strength at cut (cN)/fineness (dtex)

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

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

B. Total fineness, single yarn fineness

After setting the fiber sample in a measuring machine of 1.125m/circumference, rotating it 500 times to make a loop-shaped reel, and drying it with a hot air dryer (105±2℃×60min), measure the mass of the reel with a thousand pyeong and multiply the process moisture content The fineness was calculated from the value. In addition, the process moisture content was made into 4.5 %.

C. Sulfuric Acid Relative Viscosity (ηr)

0.25 g of a polyamide chip sample or a fiber sample was melt|dissolved so that it might become 1 g with respect to 100 ml of sulfuric acid of 98 mass % concentration, and the flow time (T1) at 25 degreeC was measured using the Oswald type viscometer. Then, the flow time (T2) of only sulfuric acid with a density|concentration of 98 mass % was measured. The ratio of T1 to T2, ie, T1/T2, was taken as the sulfuric acid relative viscosity.

D. Thread Non-uniformity (U%)

A fiber sample was measured using a USTER TESTER IV manufactured by zellweger uster at a sample length of 500 m, a measurement yarn speed V: 100 m/min, Twister: S, 30000/min, and 1/2 Inert.

E. Deterministic, rigid non-quantitative

(Xc) calculated the difference (?Hm-?Hc) between the amount of heat of fusion and heat of cold crystallization by the DSC method, and was calculated by Equation (1). where ΔHm0 is the heat of fusion of the crystalline polyamide, and its value is 229.76 J/g.

In addition, the rigid non-quantitation (Xra) was computed by the formula (2) from the crystallinity degree (Xc) and the movable non-quantitation (Xma). The moving specific quantity (Xma) was calculated from the specific heat change (ΔCp) before and after the glass transition on the temperature-heat flux reversible curve by the temperature modulation DSC method (TMDSC). Here, ΔCp used a specific heat gap before and after glass transition calculated by extrapolating a tangent to a temperature-heat flow reversible curve before and after glass transition. The movable specific quantity (Xma) was computed by Formula (3). Here, ΔCp0 is the specific heat difference before and after Tg of the amorphous polyamide, and its value is 0.4745 J/g.

In addition, the stiffness non-quantitation was computed from the average value of two measurements of temperature-modulated DSC and DSC.

Crystalline amount: Xc(%)=(ΔHm-ΔHc)/ΔHm0×100... (1)

Spasticity non-quantitative: Xra(%)=100-(Xc+Xma) ...(2)

Moving non-quantitation: Xma(%)=ΔCp/ΔCp0×100····(3).

In addition, the measurement conditions of normal DSC and temperature modulation DSC were implemented on the following conditions.

(a) Normal DSC

Data processing was performed by Universal Analysis 2000 using Q1000 manufactured by TA Instruments. The measurement was carried out under nitrogen flow (50 mL/min) in a temperature range of 0 to 300° C., a temperature increase rate of 10° C./min, and a sample weight of about 5 mg (caloric data is normalized to the weight after measurement).

The detail of the said DSC method is described in the following [Document 1].

[Document 1]

Wunderlich B., Thermal Analysis of Polymeric Materials, Appendix 1 (The ATHAS Data Bank), Springer (2005).

(b) temperature modulated DSC

Data processing was performed by Universal Analysis 2000 using Q1000 manufactured by TA Instruments. Measurement was carried out under nitrogen flow (50 mL/min) in a temperature range of 0 to 200°C, a temperature increase rate of 2°C/min, and a sample weight of about 5 mg (caloric data is normalized to the weight after measurement).

The method is a method of measuring by increasing the average temperature while repeating heating and cooling at a certain period and amplitude, and reversible components such as glass transition (Reversing Heat Flow) and the total DSC signal (Total Heat Flow), It can be separated into irreversible components (Nonreversing Heat Flow) such as enthalpy relaxation, hardening reaction, and solvent removal. However, the melting peak of the crystal appears in both the reversible component and the irreversible component.

The detail of the said temperature modulation DSC method is described in the said [Document 1].

F. Evaluation of the race

(a) softness

The softness of the lace products was evaluated relative to the testers (five people) who had extensive experience in tactile evaluation. As a result, the average value of the evaluation points of each inspector was rounded off, and the average value was 5 as S, 4 as A, 3 as B, and 1-2 as C.

5 points: very good

4 points: slightly superior

3 points: average

2 points: slightly behind

1 point: lagging behind.

S and A were set as the softness pass.

(b) durability

The rupture strength was measured according to the rupture strength test method by JIS L1096-2010 and the Mullen type method (method A), and the rupture strength of three arbitrary places was measured, and the following standard evaluated 4 steps from the average value.

S: 130 kPa or more

A: 100kPa or more and less than 130kPa

B: 90 kPa or more and less than 100 kPa

C: Less than 90 kPa.

S and A were made into durability pass.

(c) dignity

The degree of uneven dyeing of the inspectors (5 persons) was evaluated relative to the lace product. As a result, the average value of the evaluation points of each inspector was rounded off, and the average value was 5 as S, 4 as A, 3 as B, and 1-2 as C.

5 points: very good

4 points: slightly superior

3 points: average

2 points: slightly behind

1 point: lagging behind

S and A were regarded as passing grades.

(d) process passability

Knitting operability: The number of single yarns during knitting was defined as the number of single yarns per one piece of lace fabric (80 m), and expressed according to the following criteria.

S: 0 or more but less than 5

A: More than 5 but less than 10

B: 10 or more but less than 20

C: 20 or more but less than 30

S and A were made into process passability pass.

G. Assessment of stockings

(a) softness

Regarding the stocking product, the softness of the leg part was evaluated relative to the testers (5 people) who were experienced in tactile evaluation while wearing the human foot model. As a result, the average value of the evaluation points of each inspector was rounded off, and the average value was 5 as S, 4 as A, 3 as B, and 1-2 as C.

5 points: very good

4 points: slightly superior

3 points: average

2 points: slightly behind

1 point: lagging behind

S and A were set as the softness pass.

(b) durability

Put the stocking product on the model of the human foot with the outside facing out, and after setting the garter part at a position of 60 cm from the heel to the thigh, 52.5 cm from the heel to the thigh as the center, and the inner side of the thigh of the foot model. In accordance with the size of the measuring frame, a circle mark was pasted. When fixing the product to the measurement frame, by fixing it according to the previously attached circular mark, the burst strength was measured in the same state as the worn state, and it was set as an index of durability.

The rupture strength was measured according to the rupture strength test method by JIS L1096-2010 and the Mullen type method (method A), and the rupture strength of three arbitrary places was measured, and the following standard evaluated 4 steps from the average value.

S: 117.7 kPa or more

A: More than 98.1 kPa and less than 117.7 kPa

B: 88.3 kPa or more and less than 98.1 kPa

C: Less than 88.3 kPa.

S and A were made into durability pass.

(c) dignity

The degree of staining unevenness of the inspector (5 persons) was evaluated relative to the stocking product. As for the result, the average value of the average value of the evaluation points of each inspector was rounded off, and the average value made 5 to S, 4 to A, 3 to B, and 1-2 to C.

5 points: very good

4 points: slightly superior

3 points: average

2 points: slightly behind

1 point: lagging behind.

S and A were regarded as passing grades.

(d) process passability

The following criteria evaluated the number of weaving due to yarn breakage at the time of knitting by continuously operating the stocking at a rotation speed of 400 rpm with a socks knitting machine for 1 hour.

S: thread break less than 2 times,

A: Thread breaks 2 or more times and less than 4 times;

B: Thread break 4 times or more but less than 6 times;

C: Thread break 6 times or more.

S and A were made into process passability pass.

[Example 1]

(Production of polyamide multifilaments)

As polyamide, nylon 6 chips having a sulfuric acid relative viscosity (ηr) of 3.3 and a melting point of 225°C were dried by a conventional method so as to have a moisture content of 0.03% by mass or less. The obtained nylon 6 chips were melted at a spinning temperature (melting temperature) of 290°C, and discharged from a spinneret. As for the spinneret, the number of holes 42, a spherical shape, a hole diameter of φ 0.25 mm, and a 6 thread/spindle were used.

The spinning machine spun using the spinning machine (direct spinning stretching machine) of the aspect shown in FIG. In addition, as the heating tube, a two-layer heating tube having a heating tube length (L) of 50 mm and a single layer length (L1, L2) of 25 mm is used, and the atmospheric temperature of the upper layer heating tube is 300 ° C. The temperature was set so that the atmospheric temperature of 150 ° C.

Each filament discharged from the spinneret is slowly cooled at an atmospheric temperature of 150 to 300 ° C in a two-layer heating tube, and passed through an annular cooling device of cold air with a cooling start distance (LS) of 169 mm and 18 ° C. Cooled and solidified. After that, the oil agent is applied at the oil supply position (Lg) from the nozzle surface at a position of 1300 mm, each filament is focused to form multifilaments, and entangled with a fluid entanglement nozzle device, and then the take-up roller speed (spinning Speed) 1500 m/min, a heat set length of 600 mm, and a draw ratio of 2.8 through a drawing roller heated to 155° C., and winding was performed to obtain a nylon 6 multifilament of 22.0 dtex and 7 filaments.

Table 1 shows the results of evaluation of the obtained nylon 6 multifilament.

(Manufacture of lace knitting)

Next, the above multifilaments were fixed and knitted together with a runner length of 21.0 cm as a back side yarn of a 28G lacquer lace back side yarn, a runner length of 100.0 cm as a front side yarn of the backing yarn, and a winding yarn of 235 to 330 dtex. . Next, a lace knitted fabric for an inner was obtained by scouring, dyeing, and setting the finish. Table 1 shows the results of evaluation of the obtained lace products.

[Example 2]

The ambient temperature of the upper layer heating tube is set to 300 ° C, and the atmospheric temperature of the lower layer heating tube is set to 100 ° C, and the temperature is set to 100 ° C. Except that, in the same manner as in Example 1, nylon 6 multifilaments of 22 dtex and 7 filaments were obtained to obtain a lace knitted fabric. An evaluation result is shown in Table 1.

[Example 3]

The temperature was set so that the atmospheric temperature of the upper heating tube was 300 ° C. and the atmospheric temperature of the lower heating tube was 200 ° C., and slowly cooled at an atmospheric temperature of 200 to 300 ° C. in the heating tube, except that the draw ratio was 3.0 times as in Example 1 In the same manner, a lace knitted fabric was obtained by obtaining a nylon 6 multifilament of 22 dtex and 7 filaments. An evaluation result is shown in Table 1.

[Example 4]

A nylon 66 multifilament of 22 dtex and 7 filaments was obtained in the same manner as in Example 1 except that a nylon 66 chip having a sulfuric acid relative viscosity (ηr) of 3.2 and a melting point of 265°C was used as the polyamide to obtain a lace knitted fabric. An evaluation result is shown in Table 1.

[Comparative Example 1]

For the heating tube, a single-layer heating tube having a heating tube length (L) of 50 mm was used, and the temperature was set so that the atmospheric temperature was 300 ° C., and the draw ratio was 3.2 times. 6 Multifilaments were obtained to obtain a lace knitted fabric. An evaluation result is shown in Table 1.

Because of the single-layer heating tube, the atmospheric temperature in the heating tube became constant, and the thermal convection in the heating tube was disturbed, and U% deteriorated. In addition, since the atmospheric temperature setting in the heating cylinder was 300° C., which was close to the radiation temperature, the orientation relaxation by slow cooling from the nozzle surface to the upper surface of the cooling device 4 was not sufficient, and the 15% strength was high. As a result, the processability, quality, and softness of lace knitting were inferior.

[Comparative Example 2]

The temperature was set so that the atmospheric temperature of the upper heating tube was 200 ° C and the atmospheric temperature of the lower heating tube was 100 ° C. In the same manner as in Example 1, nylon 6 multifilaments of 22 dtex and 7 filaments were obtained to obtain a lace knitted fabric. An evaluation result is shown in Table 1.

Since the ambient temperature setting in the heating tube is 100 to 200 ° C, which is 90 ° C or more lower than the radiation temperature, the orientation relaxation by slow cooling from the nozzle surface to the upper surface of the cooling device 4 is not sufficient, so the strength is 15% The intensity was low. Therefore, the durability of the lace knitting was inferior.

[Comparative Example 3]

A lace knitted fabric was obtained by obtaining 22 dtex and 7-filament nylon 6 multifilaments in the same manner as in Example 1 except that a heating tube was not provided. An evaluation result is shown in Table 1.

Since the heating cylinder was not provided, orientation relaxation by slow cooling from the nozzle surface to the upper surface of the cooling device 4 was insufficient, and the strength of 15% was low. Therefore, the durability of the lace knitting was inferior.

[Example 5]

A lace knitted fabric was obtained by obtaining 22 dtex, 7-filament nylon 6 multifilaments in the same manner as in Example 1, except that the oil supply position (Lg) was set to 800 mm and the draw ratio was 3.0 times. Table 2 shows the evaluation results.

[Example 6]

A lace knitted fabric was obtained by obtaining 22 dtex, 7-filament nylon 6 multifilaments in the same manner as in Example 1, except that the oil supply position (Lg) was set to 1500 mm and the draw ratio was 2.7 times. Table 2 shows the evaluation results.

[Comparative Example 4]

A lace knitted fabric was obtained by obtaining 22 dtex, 7-filament nylon 6 multifilaments in the same manner as in Example 1, except that the oil supply position (Lg) was set to 600 mm and the draw ratio was 3.2 times. Table 2 shows the evaluation results.

U% deteriorated because the oil agent was applied in a state where the filament temperature did not drop to room temperature. In addition, the yarn bending from the nozzle face to the oil supply guide was large, and the tensile strength and 15% strength were low due to the influence of abrasion in the oil supply guide. As a result, the processability, durability, and quality of lace knitting were inferior.

[Comparative Example 5]

A lace knitted fabric was obtained by obtaining 22 dtex, 7-filament nylon 6 multifilaments in the same manner as in Example 1, except that the oil supply position (Lg) was set to 3000 mm and the draw ratio was 2.7 times. Table 2 shows the evaluation results.

The effect of the yarn fluctuations due to the downdraft was large, and the U% deteriorated. In addition, the 15% strength and elongation were low because the spinning tension increased due to the influence of the water flow and the spinning orientation progressed. As a result, the quality and durability of lace knitting were inferior.

[Example 7]

A nylon 6 multifilament of 22 dtex and 7 filaments was obtained in the same manner as in Example 1 except that the take-up roller speed (spinning speed) was 1000 m/min and the draw ratio was 3.8 times to obtain a lace knitted fabric. Table 2 shows the evaluation results.

[Example 8]

A nylon 6 multifilament of 22 dtex and 7 filaments was obtained in the same manner as in Example 1, except that the take-up roller speed (spinning speed) was 2000 m/min and the draw ratio was 2.3 times to obtain a lace knitted fabric. Table 2 shows the evaluation results.

[Comparative Example 6]

A nylon 6 multifilament of 22 dtex and 7 filaments was obtained in the same manner as in Example 1 except that the take-up roller speed (spinning speed) was 800 m/min and the draw ratio was 4.5 times to obtain a lace knitted fabric. Table 2 shows the evaluation results.

Because the spinning speed is low, the spinning tension is low, and the effect of yarn fluctuations is large, so that the U% is deteriorated. In addition, the slow cooling effect of the heating tube was increased, and the strain relaxation of the polyamide molecular chain was excessively advanced, so that the strength by 15% was high. As a result, the processability, quality, and softness of lace knitting were inferior.

[Comparative Example 7]

A nylon 6 multifilament of 22 dtex and 7 filaments was obtained in the same manner as in Example 1, except that the take-up roller speed (spinning speed) was 2500 m/min and the draw ratio was 1.9 times to obtain a lace knitted fabric. Table 2 shows the evaluation results.

Because the spinning speed was high, the strain rate was high, and the variation in the strain rate increased, so that the draft elongation non-uniformity increased and the U% deteriorated. In addition, the slow cooling effect of the heating tube was lowered, and the strain relief of the polyamide molecular chain was insufficient, resulting in low strength and elongation by 15%. As a result, the quality and durability of lace knitting were inferior.

[Example 9]

A lace knitted fabric was obtained by obtaining 22 dtex and 7-filament nylon 6 multifilaments in the same manner as in Example 1 except that stretching rollers having different diameters were used and the row set length was 1200 mm. Table 2 shows the evaluation results.

[Comparative Example 8]

Using stretching rollers of different diameters, except that the row set length was set to 1800 mm, 22 dtex and 7 filament nylon 6 multifilaments were obtained in the same manner as in Example 1 to obtain a lace knitted fabric. Table 2 shows the evaluation results.

The crystallization of the fiber by heat was excessively advanced, resulting in high strength by 15%. Therefore, the process passability and softness of the lace knitting were inferior.

[Example 10]

(Production of polyamide multifilaments)

As polyamide, nylon 6 chips having a sulfuric acid relative viscosity (ηr) of 3.3 and a melting point of 225°C were dried by a conventional method so as to have a moisture content of 0.03% by mass or less. The obtained nylon 6 chips were melted at a spinning temperature (melting temperature) of 290°C, and discharged from a spinneret. As for the spinneret, the number of holes 30, spherical shape, hole diameter φ 0.20mm, and 6 thread/spindle were used.

The spinning machine spun using the spinning machine of the aspect shown in FIG. In addition, as the heating tube, a two-layer heating tube having a heating tube length (L) of 50 mm and a single layer length (L1, L2) of 25 mm is used, and the atmospheric temperature of the upper layer heating tube is 300 ° C. The temperature was set so that the atmospheric temperature of 150 ° C.

Each filament discharged from the spinneret is slowly cooled at an atmospheric temperature of 150 to 300 ° C in a two-layer heating tube, and passed through an annular cooling device of cold air with a cooling start distance (LS) of 169 mm and 18 ° C. Cooled and solidified. After that, the oil agent is applied at the oil supply position (Lg) from the nozzle surface at a position of 1300 mm, each filament is focused to form multifilaments, and entangled with a fluid entanglement nozzle device, and then the take-up roller speed (spinning Speed) 1500 m/min, heat set length of 600 mm, and stretched at a draw ratio of 2.6 through a drawing roller heated to 155° C., and wound up to obtain a nylon 6 multifilament of 8.0 dtex and 5 filaments.

Table 3 shows the results of evaluation of the obtained nylon 6 multifilament.

(Manufacturing of stockings)

Then, the multifilament is used for the covering yarn of the covering yarn, and the draft is set to 3.0 times with a polyurethane elastic yarn of 22 dtex as the central yarn, and a single covering is performed with a twist number of 2400 t/m (S, Z directions) to form a single covering elastic yarn (SCY). was manufactured

Using the obtained SCY, it knitted with a sock knitting machine. Then, the raw pieces were refined, dyed, and final set was performed at 120°C for 30 seconds to obtain a pantyhose product. Table 3 shows the results of evaluating the leg portion of the obtained pantyhose product.

[Comparative Example 9]

A stocking product was obtained by obtaining 8 dtex and 5-filament nylon 6 multifilaments in the same manner as in Example 10 except that a heating tube was not installed. Table 3 shows the evaluation results.

Since the heating cylinder was not provided, orientation relaxation by slow cooling from the nozzle surface to the upper surface of the cooling device 4 was insufficient, and the strength of 15% was low. Therefore, the durability of the stocking product was inferior.

[Comparative Example 10]

Without installing a heating tube, a nylon 6 multifilament of 8 dtex and 5 filaments was obtained in the same manner as in Example 10 except that the take-up roller speed (spinning speed) was 2500 m/min and the draw ratio was 1.5 times to obtain a stocking product. Table 3 shows the evaluation results.

Since the spinning rate was high, the variation in the strain rate increased due to the increase in the strain rate, and the draft elongation nonuniformity increased and the U% deteriorated. Moreover, since the heating cylinder was not provided, the deformation relief by slow cooling from the nozzle surface to the upper surface of the cooling device 4 was insufficient, and 15% strength and elongation were low. As a result, the quality and durability of stocking products were inferior.

[Comparative Example 11]

For the heating tube, a single-layer heating tube with a heating tube length (L) of 50 mm is used, the temperature is set so that the atmospheric temperature is 300 ° C., the oil supply position (Lg) is 3000 mm, the take-up roller speed (spinning speed) 600 m/min, elongation In the same manner as in Example 10, except that the magnification was increased to 4.5 times, nylon 6 multifilaments of 8 dtex and 5 filaments were obtained to obtain a stocking product. Table 3 shows the evaluation results.

Because of the single-layer heating tube, the atmospheric temperature distribution within the heating tube becomes constant, and the thermal convection in the heating tube is disturbed. Also, the effect of yarn fluctuations due to the low oil supply position (long distance from the nozzle to the oil supply) and the low radiation speed. This large U% worsened. In addition, due to the low spinning speed, the slow cooling effect of the heating tube was increased, and the strain relaxation of the polyamide molecular chain was excessively advanced, and the crystallization of the fiber by the heat setting length was excessively advanced, so that the 15% strength was high. For this reason, the process passability, quality, and softness of the stocking product were inferior.

1: spinneret 2: gas ejection device
3: heating barrel 4: cooling device
5: Oil supply device 6: Fluid entanglement nozzle device
7: take-up roller 8: draw roller
9: Winding device L: Multi-layer heating tube length
L1: Single-layer length of multi-layer heating trough LS: Cooling start distance
Lg: refueling position

Claims (6)

Total fineness 4.0 to 33.0 dtex, single yarn fineness 1.3 to 3.4 dtex, tensile strength at 15% elongation of 4.0 to 6.0 cN/dtex, tensile strength of 10.0 cN/dtex or more, and yarn non-uniformity (U%) of 1.2 or less Polyamide multifilament. The method of claim 1,
Polyamide multifilament, characterized in that the elongation is 30-50%. 3. The method of claim 1 or 2,
Polyamide multifilament, characterized in that the sum of the crystalline amount and the rigid non-quantitative amount is 70 to 90%. A lace knitted fabric using the polyamide multifilament according to claim 1 or 2 for a lace base yarn. A stocking in which the polyamide multifilament according to claim 1 or 2 is used as a covering yarn, and the covering yarn is partially used.
delete

Images