WO2021020354A1

WO2021020354A1 - Polyamide composite fiber and finished yarn

Info

Publication number: WO2021020354A1
Application number: PCT/JP2020/028737
Authority: WO
Inventors: 儒黄; 純郎山口
Original assignee: 東レ株式会社
Priority date: 2019-07-31
Filing date: 2020-07-27
Publication date: 2021-02-04
Also published as: KR20220038683A; CN114207200A; EP4006216A1; TW202113178A; JPWO2021020354A1; EP4006216A4

Abstract

The present invention addresses the problem of providing a polyamide composite fiber obtained from a woven or knitted fabric having excellent stretchability or a finished yarn comprising the same. This polyamide composite fiber is an eccentric core-in-sheath type of polyamide composite fiber comprising two kinds of crystalline polyamide (A) and crystalline polyamide (B) differing in composition from each other, wherein the water absorptivity and thermal contraction stress of the polyamide composite fiber after being left to stand still for 72 hours in an environment in which the temperature is 30℃ and the relative humidity is 90 RH% are 5.0% or less and 0.15 cN/dtex or more, respectively.

Description

Polyamide composite fiber and processed yarn

The present invention relates to an eccentric core sheath type composite fiber made of polyamide and a processed yarn made of it.

Conventionally, polyamide fibers are softer and have a better touch than polyester fibers, and are widely used for clothing applications. Single fiber yarns made of one type of polymer, such as nylon 6 and nylon 66, which are representative of polyamide fibers for clothing, have almost no elasticity in the fibers themselves, so they are given elasticity by false twisting or the like. , Used for elastic woven and knitted fabrics. However, it has been difficult to obtain a woven or knitted fabric having sufficiently satisfactory elasticity by subjecting such a single fiber yarn to a process such as false twisting.

Therefore, a method of obtaining elastic woven or knitted fabrics by using elastic fibers, or a latent crimping performance that develops crimping by heat treatment such as a dyeing process by using two kinds of polymers having different properties in combination. A method of obtaining a stretchable woven or knitted fabric by using a composite fiber having a structure has been proposed (see Patent Document 1). Further, as a polyamide composite fiber having latent crimping performance, a composite fiber in which two types of polyamides having different viscosities are arranged in a side-by-side type or an eccentric core sheath type has also been proposed (see Patent Document 2).

Further, by using a highly heat-shrinkable polyamide composite fiber containing an amorphous polyamide or a processed yarn made of the same, even if a wet heat or a dry heat treatment is performed while a high tension is applied in the warp yarn direction, the stress exceeds the binding force of the woven or knitted fabric. There have been proposed composite fibers and processed yarns that can shrink in the warp yarn direction and exhibit crimpability in the warp yarn direction (see Patent Document 3).

International Publication No. 2018/110523 Japanese Patent Application Laid-Open No. 2002-363827 International Publication No. 2017/221713

However, when the composite fiber described in Patent Document 1 is obtained from two types of polyamides having different properties, the stretchability is lost by passing through processing steps such as a refining step and a dyeing step due to the swelling property peculiar to the polyamide. In some cases, the product did not provide sufficient stretch. The same applies to the polyamide composite fiber described in Patent Document 2.

Furthermore, even if the composite fiber composed of the polyamide described in Patent Document 2 has excellent crimpability in the state of the raw yarn and the processed yarn, the moist heat of the scouring and dyeing processing of the woven and knitted fabric is performed. In the process, wrinkles peculiar to polyamide fibers are likely to occur, and in the dry heat process of the heat setting process, it is difficult to remove the wrinkles formed in the moist heat process. Therefore, in order to maintain the quality of the woven and knitted article, the woven and knitted material is used in the moist heat process. It is necessary to process while applying tension to the fiber. As described above, in the polyamide composite fiber described in Patent Document 2, the crimping of the raw yarn and the processed yarn cannot be sufficiently expressed by applying tension to the woven or knitted fabric in the moist heat process, resulting in stretching. There is a problem that the woven and knitted fabric has poor properties.

Further, in the highly heat-shrinkable polyamide composite fiber described in Patent Document 3, since the amorphous polyamide polymer promotes moisture absorption and crystallization with time, the shrinkage property also deteriorates with time, and a woven or knitted fabric having low stretchability may be obtained.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a polyamide composite fiber capable of obtaining a woven or knitted fabric having excellent stretchability, and a processed yarn made of the polyamide composite fiber.

The polyamide composite fiber of the present invention is an eccentric core-sheath type polyamide composite fiber composed of two types of crystalline polyamide (A) and crystalline polyamide (B) having different compositions, and the temperature of the polyamide composite fiber is 30 ° C. A polyamide composite fiber having a water absorption rate of 5.0% or less and a heat shrinkage stress of 0.15 cN / dtex or more after being allowed to stand for 72 hours in an environment with a relative humidity of 90 RH%.
According to a preferred embodiment of the polyamide composite fiber of the present invention, the amount of rigid amorphous of the above-mentioned polyamide composite fiber is 40 to 60%, and the expansion / contraction elongation rate is 30% or more.
According to a preferred embodiment of the polyamide composite fiber of the present invention, the crystalline polyamide (A) is nylon 6 or a copolymer thereof.
According to a preferred embodiment of the polyamide composite fiber of the present invention, the crystalline polyamide (B) is nylon 610 or a copolymer thereof.
According to a preferred embodiment of the polyamide composite fiber of the present invention, the crystalline polyamide (A) is a core component and the crystalline polyamide (B) is a sheath component.
In the present invention, a processed yarn made of the above-mentioned polyamide composite fiber is obtained.
According to the preferred embodiment of the processed yarn of the present invention, the expansion / contraction rate is 100% or more.

According to the present invention, it is possible to obtain a polyamide composite fiber and a processed yarn from which a woven or knitted fabric having excellent stretchability can be obtained. Further, according to the present invention, even if moist heat or dry heat is applied in a state where a high tension is applied in the warp direction, the woven or knitted material contracts with a stress exceeding the binding force, and the crimpability is sufficiently exhibited in the warp direction. It is possible to obtain a polyamide composite fiber and a processed yarn which can give a woven or knitted fabric having excellent stretchability.

FIG. 1 is a model cross-sectional view illustrating a cross section of the eccentric core sheath type polyamide composite fiber of the present invention. 2 (A) to 2 (C) are model cross-sectional views illustrating a cross section of another eccentric core sheath type polyamide composite fiber of the present invention.

Hereinafter, the polyamide composite fiber of the present invention and the processed yarn using the same will be described.
In addition, in this specification, "mass" is synonymous with "weight".

The polyamide composite fiber of the present invention is an eccentric core-sheath type polyamide composite fiber composed of two types of crystalline polyamide (A) and crystalline polyamide (B) having different polymer compositions, and the temperature of the polyamide composite fiber is 30 ° C. The polyamide composite fiber is characterized in that the water absorption rate after standing for 72 hours in an environment of relative humidity of 90 RH% is 5.0% or less, and the heat shrinkage stress is 0.15 cN / dtex or more.

The polyamide composite fiber of the present invention is an eccentric core-sheath type composite fiber, and is composed of two types of crystalline polyamide (A) and crystalline polyamide (B) having different polymer compositions. The eccentric core-sheath type polyamide composite fiber refers to a composite fiber in which two or more types of polyamide form an eccentric core-sheath structure.

The polyamide composite fiber of the present invention needs to have a composite cross section formed by bonding two types of crystalline polyamides, and two types of crystalline polyamides having different polymer compositions are not substantially separated. It exists in a joined state. In the present invention, it is an eccentric core sheath type in which the crystalline polyamide (A) is used as a core component, the crystalline polyamide (B) is used as a sheath component, and the crystalline polyamide (A) is covered with the crystalline polyamide (B). Is preferable.

Here, the eccentricity referred to in the present invention means that the position of the center of gravity of the core component is different from the center of the cross section of the composite fiber in the cross section of the polyamide composite fiber.

FIG. 1 is a model cross-sectional view illustrating a cross section of the eccentric core sheath type polyamide composite fiber of the present invention (hereinafter, also referred to as “polyamide eccentric core sheath type composite fiber”). In FIG. 1, the polyamide eccentric core sheath type composite fiber 10A is composed of a core component (crystalline polyamide (A)) 1 and a sheath component (crystalline polyamide (B)) 2, and is a core component crystalline polyamide. The position of the center of gravity of (A) is different from the center of the cross section of the composite fiber.

2 (A) to 2 (C) are model cross-sectional views illustrating the cross section of the other polyamide eccentric core sheath type composite fiber of the present invention. 2 (A), 2 (B) and 2 (C) show the eccentric core sheath type core component (crystalline polyamide (A)) 1 and sheath component (crystalline polyamide (B)) 2, respectively. The aspects of the polyamide eccentric core sheath type composite fibers 10B to 10C having different shape arrangement states are shown, and the position of the center of gravity of the crystalline polyamide (A), which is the core component, is different from the center of the composite fiber cross section as in FIG. ing.

The composite ratio of the crystalline polyamide (A) and the crystalline polyamide (B) is preferably crystalline polyamide (A): crystalline polyamide (B) = 6: 4 to 4: 6 (mass ratio). It is an aspect. By preferably setting the mass ratio to 6: 4 to 4: 6 in this way, the water absorption rate of the polyamide composite fiber of the present invention can be controlled to 5.0% or less, and the obtained woven or knitted fabric can be obtained. Is given excellent stretchability.

The polyamide composite fiber of the present invention is composed of two types of crystalline polyamides having different polymer compositions. The crystalline polyamide is a polyamide that forms crystals and has a melting point, and is a polymer in which so-called hydrocarbon groups are linked to the main chain via an amide bond. Specific examples of the crystalline polyamide include polypolyamide, polyhexamethylene adipamide, polyhexamethylene sebacamide, polytetramethylene adipamide, and condensation polymerization of 1,4-cyclohexanebis and a linear aliphatic dicarboxylic acid. Examples thereof include type polyamides and copolymers thereof or mixtures thereof. However, it is preferable to use a homopolyamide from the viewpoint of easy reproduction of a uniform system and stable function expression.

Examples of the crystalline polyamide (A) include nylon 6, nylon 66, nylon 4, nylon 610, nylon 11, nylon 12, and the like, and copolymers containing them as main components, which are different from the crystalline polyamide (B). A type of polyamide. The crystalline polyamide (A) can contain components other than lactam, aminocarboxylic acid, diamine and dicarboxylic acid in its repeating structure as long as the effects of the present invention are not impaired. However, from the viewpoint of yarn-making property and strength, elastomers containing polyols and the like in the repeating structure are excluded.

Further, from the viewpoint of yarn-making property, strength and peeling resistance, the crystalline polyamide (A) is a polymer in which 90% or more of the repeating structure is a single lactam, an aminocarboxylic acid or a combination of diamine and dicarboxylic acid. It is preferable, more preferably 95% or more of the repeating structure. From the viewpoint of thermal stability, it is particularly preferable that such a component is nylon 6 or a copolymer thereof.

Further, the crystalline polyamide (B) can be obtained, for example, by a combination of a dicarboxylic acid unit containing a sebacic acid unit as a main component and a diamine unit. Of these, nylon 610 and its copolymer, which have stable polymerizability, less yellowing of crimped yarn, and good dyeability, are most preferably used. Here, sebacic acid can be produced, for example, by refining from castor oil seeds, and is positioned as a plant-derived raw material.

Examples of the dicarboxylic acid constituting the dicarboxylic acid unit other than the sebacic acid unit include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, phthalic acid, isophthalic acid, and terephthalic acid. These can be blended as long as the effects of the present invention are not impaired.

Also, these dicarboxylic acids are preferably plant-derived dicarboxylic acids. The copolymerization amount of the dicarboxylic acid unit other than the sebacic acid unit is preferably 0 to 40 mol%, more preferably 0 to 20 mol%, and 0 to 10 mol% of the total dicarboxylic acid unit. Is a more preferable embodiment.

Examples of the diamine constituting the diamine unit include diamines having 2 or more carbon atoms, preferably diamines having 4 to 12 carbon atoms, and specific examples thereof include putrecin, 1,5-pentanediamine, hexamethylenediamine, and trimethylenediamine. , Nonanediamine, methylpentanediamine, phenylenediamine, and ethanebutol. Further, these diamines are also preferably plant-derived diamines.

In addition, if necessary, the crystalline polyamide (A) and the crystalline polyamide (B) include pigments, heat stabilizers, antioxidants, weathering agents, flame retardants, plasticizers, mold release agents, lubricants, and foaming agents. , Antistatic agent, moldability improving agent, strengthening agent and the like can be added and blended.

The polyamide composite fiber of the present invention needs to have a water absorption rate of 5.0% or less after being allowed to stand for 72 hours in an environment of a temperature of 30 ° C. and a relative humidity of 90 RH% (temperature 30 ° C. × relative humidity 90 RH%). Is. The water absorption rate referred to here is a value measured according to JIS L 1013. By setting the water absorption rate when treated at a temperature of 30 ° C. and a relative humidity of 90 RH% for 72 hours to 5.0% or less, the swelling of the polyamide fibers under moist heat conditions such as a refining process and a dyeing process is small, and these The elongation of the woven and knitted fabric during the process is reduced. This makes it possible to perform processes such as a refining process and a dyeing process without applying extra tension to the woven or knitted material. As a result, a woven or knitted fabric having excellent stretchability can be obtained.

On the other hand, the higher the water absorption rate, the more the polyamide fiber tends to swell due to water content, and when the water absorption rate exceeds 5.0%, wrinkles and wrinkles are likely to occur in the scouring, relaxing treatment process, and dyeing process. Since it is usually stretched and processed, the stretchability is reduced.

The water absorption rate is preferably 4% or less. Further, although the lower limit of the water absorption rate cannot be specified, it is practically about 1.0%.

The water absorption rate can be controlled by the polymer selection of the crystalline polyamide (A) and the crystalline polyamide (B) and the core-sheath composite ratio.

The polyamide composite fiber of the present invention needs to have a heat shrinkage stress of 0.15 cN / dtex or more. The heat shrinkage stress referred to here is a heat shrinkage stress measuring machine (for example, manufactured by Kanebo Engineering Co., Ltd., model "KE-2 type"), and the fiber threads to be measured are tied into a loop having a circumference of 16 cm to form a loop of the threads. An initial load of 1/30 g of fineness (decitex) is applied, the temperature is measured from 40 ° C to 210 ° C at a heating rate of 100 ° C / min, and the peak value of the obtained thermal stress curve is the maximum thermal stress (cN /). It is measured as dtex).

Since the heat shrinkage stress is 0.15 cN / dtex or more, even if a wet heat treatment or a dry heat treatment is performed while a high tension is applied in the warp direction, the heat shrinks with a stress superior to the textile binding force. A woven or knitted fabric that can sufficiently exhibit crimpability and has good stretchability can be obtained. When the heat shrinkage stress is less than 0.15 cN / dtex, sufficient crimping does not occur in the moist heat step of applying high tension, resulting in a woven or knitted fabric having poor stretchability.

The heat shrinkage stress is preferably 0.20 cN / dtex or more, and more preferably 0.25 cN / dtex or more. Further, if the heat shrinkage stress is too high, the stitches at the intersections of the woven fabrics are likely to be clogged and the stretchability is hindered. Therefore, the upper limit of the heat shrinkage stress is preferably 0.50 cN / dtex. The thermal shrinkage stress can be controlled by using a high-viscosity polymer and controlling the amount of rigid amorphous fibers under the thermal drawing conditions of low spinning temperature and low spinning speed and high draw ratio.

The polyamide composite fiber of the present invention preferably has a rigid amorphous amount of 40 to 60%. Rigid amorphous is an amorphous whose amount can be determined by the method described in the section of Examples, and is an intermediate state between a crystal and a movable amorphous (conventional complete amorphous). It is an amorphous substance in which the molecular motion is frozen even above the glass transition temperature (Tg) and becomes fluid at a temperature higher than Tg (for example, Minoru 10 o'clock, "DSC (3) -polymer". Glass Transition Behavior- ", Journal of the Textile Society (Fiber and Industry), Vol. 65, No. 10 (2009)).

The amount of rigid amorphous is represented by "100% -crystallinity-movable amorphous amount". In the present invention, the polyamide composite fiber includes a crystalline portion, a rigid amorphous portion, and a movable amorphous portion. The thermal shrinkage stress depends on the binding force of the rigid amorphous chain when the fiber structure is formed and the shrinkage of the mobile amorphous chain developed when the heat treatment is performed. By setting the amount of rigid amorphous in the above range, heat shrinkage stress can be developed.

The amount of rigid amorphous can be controlled by spinning. The amount of rigid amorphous can be controlled by using a high-viscosity polymer and designing the manufacturing method, as well as the heat shrinkage stress.

When the amount of rigid amorphous chain is 40% or more, the binding force of the rigid amorphous chain is exhibited, and a desired thermal shrinkage stress can be obtained without impairing the contractility of the mobile amorphous chain. Further, when the amount of rigid amorphous chain is 60% or less, the binding force of the rigid amorphous chain is exhibited, the contraction force of the mobile amorphous chain can be maintained, and a desired thermal contraction stress is obtained. be able to. The amount of rigid amorphous is preferably 45 to 55%.

The polyamide composite fiber of the present invention preferably has a stretch elongation rate of 30% or more. The expansion / contraction rate is an index of the crimpability of the raw yarn, and the higher the value, the higher the ability to develop crimp.

In the polyamide composite fiber of the present invention, when the fiber is formed, a shrinkage difference occurs due to a difference in orientation between the crystalline polyamide (A) and the crystalline polyamide (B), and crimping occurs. However, in general, polyamide fibers are prone to wrinkles in the refining and dyeing processes of woven and knitted fabrics, and are processed in a state where high tension is applied in the warp direction in order to maintain the woven and knitted article position. The shrinkage difference may decrease due to the influence of external force (high tension). In order to maintain this shrinkage difference, the raw yarn has a constant thermal shrinkage stress, so that the crimpability of the raw yarn can be maintained, and when the expansion / contraction rate is 30% or more, the stretchability is more excellent. A woven or knitted fabric with is obtained. The expansion / contraction ratio is more preferably 100 to 200%. Since the stretch elongation rate is expressed by the shrinkage difference between the crystalline polyamide (A) and the crystalline polyamide (B), the larger the shrinkage difference is, the higher the stretch stretch rate is.

The polyamide composite fiber of the present invention preferably has a total fineness of 20 to 120 dtex as a yarn. In particular, when used for sportswear, down jackets, outerwear, and innerwear, the total fineness is more preferably 30 to 90 dtex. Further, although the single fiber fineness of the polyamide composite fiber cannot be specified, it is usually used in the range of 1.0 to 5.0 dtex.

Next, a method for producing the polyamide composite fiber of the present invention by melt spinning will be described.
In the crystalline polyamide used in the present invention, the relative viscosity of the crystalline polyamide (A) is preferably 3.1 to 3.8. The relative viscosity of the crystalline polyamide (B) is preferably 2.6 to 2.8. It is more preferable that the relative viscosity ratio (A / B) of the crystalline polyamide (A) and the crystalline polyamide (B) is 1.2 to 1.4.

By selecting a crystalline polyamide having a relative viscosity in such a range, a shrinkage difference appears after the heat treatment, a three-dimensional spiral structure is formed, and crimping occurs. In addition, during the silk-reeling process, the polyamide is transferred from amorphous to crystalline by receiving heat of fusion. At this time, since the crystalline polyamide (A) having a high relative viscosity has a high molecular binding force, the rate of transition from amorphous to crystal is slower than that of the crystalline polyamide (B) having a low relative viscosity. Therefore, when the polyamide is cooled during the transition from amorphous to crystalline after ejection of the base, rigid amorphous in an intermediate state is likely to be generated, the amount of rigid amorphous of the composite fiber is increased, and the thermal shrinkage stress and the elongation / elongation rate are improved. ..

Further, the polyamide composite fiber of the present invention has a composite cross section formed by joining two types of crystalline polyamides, and the crystalline polyamide (A) as a core component is covered with the crystalline polyamide (B) as a sheath component. It is an eccentric core sheath type structure. In the case of the conventional side-by-side structure in which the crystalline polyamide (A) is not covered with the crystalline polyamide (B) which is a sheath component, the above-mentioned crystalline polyamides having a relative viscosity difference are melted and composited in a spinning pack. A cross section is formed, the polymer flow resistance is different when the base is discharged, and the difference in flow velocity tends to cause thread bending, resulting in poor operability. Therefore, in the production of the crystalline polyamide (A) and the crystalline polyamide (B) having different melt viscosities, by adopting the eccentric core sheath type structure of the present invention, stable production can be performed with ordinary equipment.

Next, the method for producing the polyamide composite fiber of the present invention by melt spinning and composite spinning will be described.

First, a method for producing a melt-spun polyamide composite fiber of the present invention by high-speed direct spinning will be described below as an example.
The crystalline polyamide (A) and the crystalline polyamide (B) are melted separately, weighed and transported using a gear pump, and a composite flow is formed so as to form a core-sheath structure by a normal method as it is, and an eccentric core is formed. Using a sheath-type composite fiber spinneret, the spinneret is discharged from the spinneret so as to have a cross section illustrated in FIG. The discharged polyamide composite fiber yarn is cooled to 30 ° C. by blowing cooling air with a yarn cooling device such as a chimney. Subsequently, the cooled yarn is refueled and converged by the refueling device, and is picked up by the take-up roller at 1500 to 4000 m / min, passed through the take-up roller and the draw roller, and at that time, the circumference of the take-up roller and the draw roller. Stretch at 1.5-3.0 times according to the rate ratio. Further, the yarn is heat-set by a drawing roller and wound into a package at a winding speed of 3000 m / min or more.

Separately, a method for producing the melt spinning of the polyamide composite fiber of the present invention by high-speed direct spinning will be described below as an example.
Crystalline polyamide (A) and crystalline polyamide (B) are melted separately, weighed and transported using a gear pump, and a composite flow is formed so as to take a core-sheath structure by the usual method, and the eccentric core is formed. Using a sheath-type composite fiber spinneret, the spinneret is discharged from the spinneret so as to have a cross section illustrated in FIG. The discharged polyamide composite fiber yarn is cooled to 30 ° C. by blowing cooling air with a yarn cooling device such as a chimney. Subsequently, the cooled yarn is refueled and converged by the refueling device, and is picked up by the take-up roller at 3000 to 4500 m / min, passed through the take-up roller and the draw roller, and at that time, the circumference of the take-up roller and the draw roller. Finely stretch at 1.0 to 1.2 times according to the speed ratio. Further, the yarn is wound on the package at a winding speed of 3000 m / min or more.

In particular, the spinning temperature is appropriately designed based on the melting point of the crystalline polyamide (A) having a high relative viscosity. When the spinning temperature is high, the crystal portion increases and the amount of rigid amorphous tends to decrease, and when the spinning temperature is low, the amount of movable amorphous tends to increase and the amount of rigid amorphous tends to decrease slightly. Therefore, the spinning temperature is preferably 35 to 70 ° C. higher than the melting point of the crystalline polyamide (A), and more preferably 45 to 60 ° C. higher than the melting point. By appropriately setting the spinning temperature, the amount of rigid amorphous of the polyamide composite fiber of the present invention can be controlled, and a desired heat shrinkage stress and stretch elongation rate can be obtained.

Further, by appropriately designing the draft drawing (take-up speed), the amount of rigid amorphous of the polyamide composite fiber of the present invention is increased, and the heat shrinkage stress and the elongation / elongation rate are improved. The pick-up speed is preferably 1500 to 4000 m / min.

When a drawn yarn is obtained, the amount of rigid amorphous of the polyamide composite fiber of the present invention is increased and the heat shrinkage stress is improved by performing thermal drawing using the take-up roller as a heating roller. The draw ratio is preferably 1.5 to 3.0 times, more preferably 2.0 to 3.0 times. The heat stretching temperature is preferably 30 to 90 ° C, more preferably 40 to 60 ° C.

Further, by applying heat setting using the drawing roller as a heating roller, the heat shrinkage stress of the polyamide composite fiber of the present invention can be appropriately designed. The heat setting temperature is preferably 130 to 180 ° C.

It is also possible to perform entanglement using a known entanglement device in the process up to winding. If necessary, it is possible to increase the number of entanglements by adding entanglements multiple times. Furthermore, it is also possible to add an additional oil agent immediately before winding.

For the processed yarn made of the polyamide composite fiber of the present invention, the eccentric core sheath type polyamide composite fiber of the present invention is used for at least a part of the yarn. The manufacturing method of yarn processing is not limited, and examples thereof include a mixed fiber method and a false twist processing method. As the fiber mixing method, air blending, blending, composite false twisting and the like can be applied, but air blending is preferably used because the blending is easy to control and the manufacturing cost is low. As the false twisting method, it is preferable to perform false twisting by using a pin type, a friction type, a belt type or the like according to the fineness and the number of twists.

The processed yarn made of the polyamide composite fiber of the present invention preferably has a stretch elongation rate of 100% or more. By setting the expansion / contraction ratio to 100% or more, a woven or knitted fabric having excellent stretchability can be obtained by combining sufficient crimping and crimping of the false twisted yarn. The higher the stretchability and elongation rate, the higher the crimpability, but processing wrinkles are more likely to occur, and in order to suppress wrinkles, the product is manufactured with higher tension applied in the warp direction, which tends to hinder the stretchability of the woven or knitted fabric. Therefore, it is more preferable that the elongation / contraction ratio is 120 to 200%.

As described above, the processed yarn made of the polyamide composite fiber of the present invention preferably has a stretch elongation rate of 100% or more. The stretchable stretch woven knit is constructed by using at least a part of the polyamide composite fiber or the processed yarn of the present invention. According to the present invention, even when a high tension is applied in the warp yarn direction in the moist heat step, crimping can be sufficiently exhibited, and a woven or knitted fabric having excellent stretchability can be provided.

The stretchable stretchable knitted fabric made of the polyamide composite fiber or processed yarn of the present invention can be woven and knitted according to a known method. Moreover, the structure of the woven and knitted fabric is not limited.

In the case of woven fabrics, the structure may be any of plain weave, twill structure, Zhu Xi structure and their modified structure, and mixed structure depending on the intended use. In order to obtain a woven fabric with a firm texture and a feeling of swelling, a plain weave with many restraint points, a ripstop structure in which a flat structure and a stone grain, and a nanaco structure are combined is preferable.

In the case of knitted fabrics, the texture can be either a circular knitted fabric, an interlocked texture, a warp knitted half texture, a satin structure, a jacquard structure or their modified structure, or a mixed structure, depending on the intended use. However, a single tricot knitted fabric such as a half-textured fabric is preferable because the knitted fabric is thin, stable, and has an excellent elongation rate.

The use of the woven or knitted fabric made of the polyamide composite fiber or the processed yarn of the present invention is not limited, but is preferably used for clothing, and more preferably represented by down jackets, windbreakers, golf wear, rainwear and the like. It is used for sports, casual wear and women's and men's clothing. In particular, it can be suitably used for sportswear and down jackets.

Next, the polyamide composite fiber and the processed yarn of the present invention will be specifically described with reference to Examples.

A. Melting point:
Thermal analysis was performed using Q1000 manufactured by TA Instruments, and data processing was performed by Universal Analysis 2000. The thermal analysis was carried out under nitrogen flow (50 mL / min) at a temperature range of -50 to 300 ° C, a temperature rise rate of 10 ° C / min, and a chip sample mass of about 5 g (calorie data is standardized by mass after measurement). .. The melting point was measured from the melting peak.

B. Relative viscosity:
0.25 g of a polyamide chip sample was dissolved in 25 ml of sulfuric acid having a concentration of 98% by mass so as to be 1 g / 100 ml, and the flow time (T1) at a temperature of 25 ° C. was measured using an Ostwald viscometer. .. Subsequently, the flow time (T2) of sulfuric acid having a concentration of 98% by mass was measured. The ratio of T1 to T2, that is, T1 / T2, was defined as the relative viscosity of sulfuric acid.

C. Total fineness:
According to JIS L1013. A fiber sample was wound 200 times with a tension of 1/30 (g) using a measuring machine with a frame circumference of 1.125 m. Dry for 60 minutes at a temperature of 105 ° C, transfer to a desiccator, allow to cool for 30 minutes in a temperature of 20 ° C and a relative humidity of 55% RH, measure the mass of the skein, and calculate the mass per 10,000 m from the obtained value. , The total fineness of the fiber threads was calculated with the official moisture content as 4.5%. The measurement was performed 5 times, and the average value was taken as the total fineness.

D. Thermal shrinkage stress:
Using a KE-2 type heat shrink stress measuring machine manufactured by Kanebo Engineering Co., Ltd., a fiber sample was tied into a loop with a circumference of 16 cm, and an initial load of 1/30 g of the total fineness of the thread was applied to a temperature from 40 ° C to 210 ° C. The load when the temperature was changed at a temperature rising rate of 100 ° C./min was measured, and the peak value of the obtained thermal stress curve was taken as the thermal shrinkage stress.

E. Expansion and contraction rate:
The fiber sample is squeezed, soaked in boiling water at a temperature of 90 ° C. for 20 minutes, air-dried, and a load of 2 mg / d is applied for 30 seconds to determine the length A, and then a load of 100 mg / d is applied for 30 seconds. The length B was calculated. The expansion / contraction rate was calculated from the following formula.
Expansion and contraction rate (%) = [(BA) / B] × 100

F. Rigid amorphous amount:
The amount of rigid amorphous was measured using Q1000 manufactured by TA Instruments as a measuring device. The difference (ΔHm−ΔHc) between the heat of fusion (ΔHm) and the heat of cold crystallization (ΔHc) obtained from the differential scanning calorimetry (hereinafter abbreviated as DSC), and the specific heat difference (ΔCp) obtained from the temperature-modulated DSC measurement. ), Further, the theoretical value of 100% crystalline (completely crystalline) for polyamide and the theoretical value of 100% amorphous (completely amorphous) of polyamide were used. Here, ΔHm0 is the amount of heat of fusion of the polyamide (perfect crystal). Further, ΔCp0 is the specific heat difference of polyamide (completely amorphous) before and after the glass transition temperature (Tg).
The crystallinity (Xc) and the amount of movable amorphous (Xma) were determined based on the following equations (1) and (2). Further, the rigid amorphous amount (Xra) was calculated by the following equation (3). The amount of rigid amorphous was calculated from the average value obtained by measuring these twice.
(1) Xc (%) = (ΔHm−ΔHc) / ΔHm0 × 100
(2) Xma (%) = ΔCp / ΔCp0 × 100
(3) Xra (%) = 100- (Xc + Xma)

The measurement conditions for DSC and temperature-modulated DSC are shown below.
(DSC measurement)
Measuring device: Q1000 manufactured by TA Instruments
Data processing: Universal Analysis 2000 manufactured by TA Instruments
Atmosphere: Nitrogen flow (50 mL / min)
Sample amount: Approximately 10 mg
Sample container: Standard aluminum container Temperature and calorific value Calibration: High-purity indium (Tm = 156.61 ° C., ΔHm = 28.71 J / g)
Temperature range: Approximately -50 to 300 ° C
Temperature rise rate: 10 ° C / min 1st temperature rise process (first run)
(Temperature modulated DSC measurement)
Measuring device: Q1000 manufactured by TA Instruments
Data processing: Universal Analysis 2000 manufactured by TA Instruments
Atmosphere: Nitrogen flow (50 mL / min)
Sample amount: Approximately 5 mg
Sample container: Standard aluminum container Temperature and calorific value Calibration: High-purity indium (Tm = 156.61 ° C., ΔHm = 28.71 J / g)
Temperature range: Approximately -50 to 210 ° C
Heating rate: 2 ° C / min

G. Strength and elongation:
The fiber sample was measured with "TENSILON" (registered trademark) manufactured by Orientec Co., Ltd., UCT-100 under the constant speed elongation conditions shown in JIS L1013 (Chemical fiber filament yarn test method, 2010). Elongation was determined from the elongation of the point showing the maximum strength on the tensile strength-elongation curve. The strength was defined as the value obtained by dividing the maximum strength by the fineness. The measurement was performed 10 times, and the average value was taken as the intensity and elongation.

H. Water absorption rate under RH environment with temperature 30 ° C and relative humidity 90%:
According to JIS-L-1013 (2010 version), the mass was measured after standing in an absolute dry state at a temperature of 30 ° C. and a relative humidity of 90% RH for 72 hours, and the water content was measured.

I. Textile evaluation:
(A) Production of Weft A polycaprolactam (N6) (relative viscosity 2.70, melting point 222 ° C.) was used, and a spinneret having 12 spout holes was used for melt discharge at a temperature of 275 ° C. After melt-discharging, the obtained yarn is cooled, refueled and entangled, then picked up with a take-up roller of 2570 m / min, then stretched 1.7 times, heat-fixed at a temperature of 155 ° C., and wound up. Nylon 6 threads of 70 dtex 12 filaments were obtained at a speed of 4000 m / min.

(B) Production of Woven Fabric The eccentric core-sheath type polyamide composite yarns obtained in Examples 4 to 11 and Comparative Examples 1 to 3 were used as warp yarns (warp yarn density 90 yarns / 2.54 cm) and obtained in the above (a). A plain woven fabric (warp / composite fiber) was woven (meshing 40 g / cm ² ) using 6 nylon threads as weft (weft density 90 / 2.54 cm). Further, the eccentric core sheath type polyamide composite false twisted yarns obtained in Examples 1 to 3 are used as warp yarns (warp yarn density 90 yarns / 2.54 cm), and the nylon 6 yarns obtained in the above (a) are used as weft yarns. It was used for (weft density 90 yarns / 2.54 cm), and a plain woven fabric (warp yarn / processed yarn) was woven (meshing 40 g / cm ² ).
The obtained woven fabric is refined at a temperature of 80 ° C. for 20 minutes, then adjusted to pH 4 with Kayanol Yellow N5G 1% owf and acetic acid, dyed at a temperature of 100 ° C. for 30 minutes, and then at 80 ° C. Fix treatment was carried out at a temperature of 20 minutes, and finally heat treatment was carried out at a temperature of 170 ° C. for 30 seconds to improve the texture.

(C) Stretchability in the warp direction of the woven fabric (stretchability)
Using a tensile tester, the woven fabric samples having a width of 50 mm × 300 mm obtained in Examples 1 to 10 and Comparative Examples 1 to 4 were held at a grip interval of 200 mm and a tensile speed of 200 mm / min in the warp yarn direction of the woven fabric. The elongation rate when extended to 7N was measured and evaluated in the following three stages "A", "B" and "C". 15% or more was judged to have stretchability.
A (good): 20% or more B (possible): 15% or more and less than 20% C (impossible): less than 15%

[Example 1]
Nylon 6 (N6) having a relative viscosity of 3.3 and a melting point of 222 ° C. was used as the crystalline polyamide (A), and nylon 610 (N610) having a relative viscosity of 2.7 and a melting point of 225 ° C. was used as the crystalline polyamide (B). Crystalline polyamide (A) is used as a core component, crystalline polyamide (B) is used as a sheath component, and each is melted, and a crystalline polyamide (12 holes, round holes) is used for an eccentric core sheath type composite fiber spinneret. The composite ratio (mass ratio) of (A) and the crystalline polyamide (B) was melt-discharged at a ratio of crystalline polyamide (A): crystalline polyamide (B) = 5: 5 (spinning temperature 270 ° C.). The threads discharged from the mouthpiece are cooled and solidified by the thread cooling device, lubricated with a hydrous oil by the oil supply device, entangled by the fluid entanglement nozzle device, and then used by a take-up roller (room temperature 25 ° C.). It was taken up at 3700 m / min, stretched 1.1 times between stretching rollers (room temperature 25 ° C.), and then wound into a package at a winding speed of 4000 m / min. A polyamide composite fiber yarn having 62 dtex12 filaments, a stretch elongation rate of 49%, a water absorption rate of 3.8%, a heat shrinkage stress of 0.16 cN / dtex, and a rigid amorphous amount of 41% was obtained.
Using the obtained polyamide composite fiber yarn, a disc false twist is performed under the condition of a twist number (D / Y) of 1.95 in a state where a heater temperature of 190 ° C. is applied to a 1.25 draw ratio, and expansion and contraction are performed. A false twisted yarn having a ratio of 130% was obtained. The obtained false twisted yarn was used as a warp to form a woven fabric. The obtained woven fabric was excellent in stretchability. The results are shown in Table 1.

[Example 2]
62dtex12 filament, stretch elongation 53%, water absorption rate 3. In the same manner as in Example 1 except that nylon 6 (N6) having a relative viscosity of 3.6 and a melting point of 222 ° C. was used as the crystalline polyamide (A). Polyamide composite fiber yarns having an thermal shrinkage stress of 0.21 cN / dtex and a rigid amorphous amount of 46% were obtained.
The obtained polyamide composite fiber yarn was false-twisted in the same manner as in Example 1 to obtain a false-twisted yarn having a stretch elongation rate of 150%. The obtained false twisted yarn was used as a warp to form a woven fabric. The obtained woven fabric was excellent in stretchability. The results are shown in Table 1.

[Example 3]
62dtex12 filament, stretchable by the same method as in Example 1 except that a copolymer (N6 / N66) of nylon 6 and nylon 66 having a relative viscosity of 3.6 and a melting point of 200 ° C. was used as the crystalline polyamide (A). Polyamide composite fiber threads having an elongation rate of 67%, a water absorption rate of 3.6%, a heat shrinkage stress of 0.25 cN / dtex, and a rigid amorphous amount of 53% were obtained.
The obtained polyamide composite fiber yarn was false-twisted in the same manner as in Example 1 to obtain a false-twisted yarn having a stretch elongation rate of 200%. The obtained false twisted yarn was used as a warp to form a woven fabric. The obtained woven fabric had better stretchability than in Examples 1 and 2. The results are shown in Table 1.

[Example 4]
A copolymer (N6 / N66) of nylon 6 and nylon 66 having a relative viscosity of 3.6 and a melting point of 200 ° C. as the crystalline polyamide (A) has a relative viscosity of 2.7 and a melting point of 225 ° C. as the crystalline polyamide (B). Nylon 610 (N610) was used. Crystalline polyamide (A) is used as a core component, crystalline polyamide (B) is used as a sheath component, and each is melted, and a crystalline polyamide (12 holes, round holes) is used for an eccentric core sheath type composite fiber spinneret. The composite ratio (mass ratio) of (A) and the crystalline polyamide (B) was melt-discharged at a ratio of crystalline polyamide (A): crystalline polyamide (B) = 5: 5 (spinning temperature 270 ° C.). The threads discharged from the mouthpiece are cooled and solidified by the thread cooling device, lubricated with a non-hydrous oil by the oil supply device, entangled by the fluid entanglement nozzle device, and then slightly heated and taken up by a roller (temperature 50 ° C.). ) Was taken up at 1700 m / min, and after stretching 2.4 times between the heating and stretching rollers (heat setting temperature: 150 ° C.), the package was wound at a winding speed of 4000 m / min. A polyamide composite fiber yarn having 62 dtex12 filaments, a stretch elongation rate of 117%, a water absorption rate of 3.6%, a heat shrinkage stress of 0.29 cN / dtex, and a rigid amorphous amount of 55% was obtained. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric. The obtained woven fabric had better stretchability than that of Example 5. The results are shown in Table 2.

[Example 5]
Nylon 6 (N6) having a relative viscosity of 3.3 and a melting point of 222 ° C. was used as the crystalline polyamide (A), and nylon 610 (N610) having a relative viscosity of 2.7 and a melting point of 225 ° C. was used as the crystalline polyamide (B). Crystalline polyamide (A) is used as a core component, crystalline polyamide (B) is used as a sheath component, and each is melted, and a crystalline polyamide (12 holes, round holes) is used for an eccentric core sheath type composite fiber spinneret. The composite ratio of (A) and the crystalline polyamide (B) was melt-discharged at a ratio of crystalline polyamide (A): crystalline polyamide (B) = 5: 5 (spinning temperature 270 ° C.). The threads discharged from the mouthpiece are cooled and solidified by the thread cooling device, lubricated with a non-hydrous oil by the oil supply device, entangled by the fluid entanglement nozzle device, and then slightly heated and taken up by a roller (temperature 50 ° C.). ) Was taken up at 1700 m / min, and after stretching 2.4 times between the heating and stretching rollers (heat setting temperature: 150 ° C.), the package was wound at a winding speed of 4000 m / min. A polyamide composite fiber yarn having 62 dtex12 filaments, an expansion / contraction rate of 83%, a water absorption rate of 3.8%, a heat shrinkage stress of 0.20 cN / dtex, and a rigid amorphous amount of 46% was obtained. A woven fabric was formed using the obtained composite fiber threads as warp threads. The obtained woven fabric was excellent in stretchability. The results are shown in Table 2.

[Example 6]
62dtex12 in the same manner as in Example 5 except that the composite ratio of the crystalline polyamide (A) and the crystalline polyamide (B) was set to: crystalline polyamide (A): crystalline polyamide (B) = 4: 6. Polyamide composite fiber threads having a filament, a stretch elongation rate of 81%, a water absorption rate of 3.3%, a heat shrinkage stress of 0.18 cN / dtex, and a rigid amorphous amount of 45% were obtained. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric. The obtained woven fabric was excellent in stretchability. The results are shown in Table 2.

[Example 7]
62dtex12 in the same manner as in Example 5 except that the composite ratio of the crystalline polyamide (A) and the crystalline polyamide (B) was set to: crystalline polyamide (A): crystalline polyamide (B) = 6: 4. Polyamide composite fiber threads having a filament, a stretch elongation rate of 87%, a water absorption rate of 4.3%, a heat shrinkage stress of 0.23 cN / dtex, and a rigid amorphous amount of 47% were obtained. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric. The obtained woven fabric was excellent in stretchability. The results are shown in Table 2.

[Example 8]
A copolymer of nylon 6 (N6) having a relative viscosity of 3.6 and a melting point of 222 ° C. as the crystalline polyamide (A) and nylon 610 and nylon 510 having a relative viscosity of 2.7 and a melting point of 225 ° C. as the crystalline polyamide (B). 62dtex12 filament, expansion / contraction elongation 103%, water absorption rate 4.1%, heat shrinkage stress 0.20cN / dtex, rigid amorphous amount 46 in the same manner as in Example 5 except that (N610 / N510) was used. % Polyamide composite fiber threads were obtained. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric. The obtained woven fabric had better stretchability than that of Example 5. The results are shown in Table 2.

[Example 9]
The same method as in Example 5 except that the material was picked up at 2050 m / min by a slightly heated take-up roller (50 ° C.) and stretched 2.0 times between the heat-stretching rollers (heat setting temperature: 150 ° C.). A polyamide composite fiber yarn having 62 dtex12 filaments, a stretch elongation rate of 82%, a water absorption rate of 3.8%, a heat shrinkage stress of 0.18 cN / dtex, and a rigid amorphous amount of 43% was obtained. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric. The obtained woven fabric was excellent in stretchability. The results are shown in Table 2.

[Example 10]
62dtex12 filament, expansion / contraction elongation 82%, water absorption rate 3.8%, heat shrinkage stress 0.18cN / dtex, rigid amorphous amount 43% by the same method as in Example 5 except that the spinning temperature was set to 280 ° C. Polyamide composite fiber yarn was obtained. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric. The obtained woven fabric was excellent in stretchability. The results are shown in Table 2.

[Example 11]
62dtex12 filament, expansion / contraction elongation 95%, water absorption rate 3.8%, heat shrinkage stress 0.22cN / dtex, rigid amorphous amount 49% by the same method as in Example 5 except that the spinning temperature was set to 260 ° C. Polyamide composite fiber yarn was obtained. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric. The obtained woven fabric was excellent in stretchability. The results are shown in Table 2.

[Comparative Example 1]
A 62dtex12 filament polyamide composite filament was obtained in the same manner as in Example 5 except that nylon 6 (N6) having a relative viscosity of 2.7 and a melting point of 222 ° C. was used as the crystalline polyamide (A). The composite yarn of Comparative Example 1 having almost no difference in relative viscosity has a small shrinkage difference after heat treatment and a low expansion and contraction elongation rate of 13%, a heat shrinkage stress of 0.13 cN / dtex, and a rigid amorphous amount of 39. It was a low value of%. The obtained polyamide composite fiber yarn was used as a warp, and the obtained woven fabric was inferior in stretchability. The results are shown in Table 2.

[Comparative Example 2]
A 62dtex12 filament polyamide composite yarn was obtained in the same manner as in Example 5 except that the composite ratio of the polyamide (A) and the polyamide (B) was set to polyamide (A): polyamide (B) = 7: 3. .. The polyamide composite yarn of Comparative Example 2 in which the ratio of the polyamide (A) having a high water absorption rate was increased had a high water absorption rate of 5.8%. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric in the same manner as in Example 5, but since wrinkles remained, the tension was increased in the warp direction to the extent that no wrinkles remained, and as a result, stretch was performed. A woven fabric with inferior properties was obtained. The results are shown in Table 2.

[Comparative Example 3]
Nylon 6 (N6) having a relative viscosity of 3.3 and a melting point of 222 ° C. was used as the crystalline polyamide (A), and nylon 6 (N6) having a relative viscosity of 2.7 and a melting point of 225 ° C. was used as the crystalline polyamide (B). Polyamide composite fiber threads of 62dtex12 filaments were obtained in the same manner as in Example 5 except. The polyamide composite fiber yarn of Comparative Example 3 produced by using polyamides having a high water absorption rate had a high water absorption rate of 6.2%. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric in the same manner as in Example 5, but since wrinkles remained, the tension was increased in the warp direction to the extent that no wrinkles remained, and as a result, stretch was performed. A woven fabric with inferior properties was obtained. The results are shown in Table 2.

[Comparative Example 4]
62dtex12 filament, expansion / contraction elongation 53%, water absorption rate 3.8%, heat shrinkage stress 0.13cN / dtex, rigid amorphous amount 36% by the same method as in Example 5 except that the spinning temperature was set to 300 ° C. Polyamide composite fiber yarn was obtained. The obtained polyamide composite fiber yarn was used as a warp to form a woven fabric. The obtained woven fabric was inferior in stretchability. The results are shown in Table 2.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and modifications can be made without departing from the intent and scope of the invention. This application is based on a Japanese patent application (Japanese Patent Application No. 2019-141540) filed on July 31, 2019, and the entire application is incorporated by reference.

1: Core component (crystalline polyamide (A))
2: Sheath component (crystalline polyamide (B))
10A-10D: Polyamide eccentric sheath type composite fiber

Claims

An eccentric core-sheath type polyamide composite fiber composed of two types of crystalline polyamide (A) and a crystalline polyamide (B) having different compositions, wherein the polyamide composite fiber is used in an environment of a temperature of 30 ° C. and a relative humidity of 90 RH%. A polyamide composite fiber having a water absorption rate of 5.0% or less and a heat shrinkage stress of 0.15 cN / dtex or more after being allowed to stand for 72 hours.
The polyamide composite fiber according to claim 1, wherein the polyamide composite fiber has a rigid amorphous amount of 40 to 60% and a stretch elongation rate of 30% or more.
The polyamide composite fiber according to claim 1 or 2, wherein the crystalline polyamide (A) is nylon 6 or a copolymer thereof.
The polyamide composite fiber according to any one of claims 1 to 3, wherein the crystalline polyamide (B) is nylon 610 or a copolymer thereof.
The polyamide composite fiber according to any one of claims 1 to 4, wherein the crystalline polyamide (A) is a core component and the crystalline polyamide (B) is a sheath component.
A processed yarn made of the polyamide composite fiber according to any one of claims 1 to 5.
The processed yarn according to claim 6, wherein the expansion / contraction elongation rate is 100% or more.