JP2007154370A - Molded knitted fabric with shape retention function and run / fray prevention function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a formed knitted fabric having efficient and effective shape-retaining function and run/fray-stopping function. <P>SOLUTION: In the formed knitted fabric having the shape-retaining function and run/fray-stopping function, a knitted fabric containing a heat-fusible elastic fiber (excluding a knitted fabric for underbody) is wet heat-treated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molded knitted fabric having a shape maintaining function and a run / fray preventing function, and more particularly to a molded knitted fabric made of a knitted fabric including elastic fibers that are heat-sealed by wet heat treatment.

  A knitted fabric containing elastic fibers is widely worn because it has a large elongation and has a good recovery and fit from the stretched state.

  Among these knitted fabrics, molded knitted fabric is a knitted fabric that reduces the number of sewing points and knits into the shape of the product according to the unevenness of the human body, such as highly fit inner, outer / bottom, shorts, lingerie, etc. Used in knitted fabric products.

However, these molded knitted fabrics have problems such as fraying, softness, misalignment, run, curl, wire transmission (hereinafter referred to as fraying) of the knitted fabric terminal. In particular, since the terminal part curls, it is necessary to fold the end of the knitted fabric, attach a separate cloth or elastic tape, sew it, or fold it inward as a double welt to form a bag. Problems such as skin damage due to steps, seams, etc. coming into direct contact with the skin, reduced feeling of wearing such as touch and comfort, and decreased aesthetics that are easily cracked on the outer garment have not been solved. There has been a demand for a knitted fabric that can be used as it is without being sewn.
Moreover, even if the material is knitted in accordance with the unevenness of the human body, there are problems that the unevenness of the uneven portion is lost due to repeated wearing and washing, and the size of the product becomes small and difficult to wear.

  Conventionally, as a method for improving the shape holding function and preventing fraying, a special knitting is applied only to the end of the knitted fabric, or sewing is mainly used.

  For example, in a Santony single knit one-piece system circular knitting machine that has a fray-preventing function in the molding knitting machine itself, it is possible to freely put a molding hem (fray-preventing on the ear part) in a vertical direction, an oblique direction, and a curvature.

  Further, in the case of thin fabrics, a method for preventing transmission lines by using a special knitting method (buckle type) has also been proposed (Patent Document 1: JP-A-8-100305).

  However, the frayed portion had a different texture or thicker than the other portions. In addition, since the part having the fraying prevention function is determined in advance at the knitting design stage, the design at the time of cutting and sewing is limited.

In Patent Document 1, the entire fabric is thick and has no transparency, and the shrinkage rate (elongation) is low. Moreover, the touch was hard and was rough. Furthermore, since a special knitting machine and a knitting technique are required, the knitting cost is high and it is expensive.
Polyurethane elastic fibers are often used to improve fit, but when polyurethane elastic fibers are used for knitting, shape retention is relatively good, but stretchability is inferior, and the knitted fabric has knitting stripes. It was visible and lacked aesthetics. When polyurethane elastic fibers are used on the entire surface (all courses for weft knitting, all wells for warp knitting), the stretchability is remarkably improved. However, the shrinkage of the knitted fabric becomes stronger and the size after knitting is made smaller or used as a product. There were drawbacks such as smaller dimensions after washing the inside.
Increasing the wet heat treatment temperature to increase the setting rate of polyurethane elastic fibers may cause the shared fibers to become harder and the texture to decrease, etc. If the insertion ratio of polyurethane elastic fibers is greatly reduced, dimensional stability increases. However, the usage-amount ratio of a polyurethane elastic fiber becomes high and cost becomes high. In addition, the use of polyurethane elastic fibers with good setability improves shape retention, but fraying and run problems still remain, and efficient and effective shape retention functions in the clothing field, particularly in the field of molded knitted fabric products. In addition, a molded knitted fabric having a function of preventing run and fraying has been demanded.

JP-A-8-100305

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a molded knitted fabric having an efficient and effective shape holding function and a run / fray preventing function.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have determined that a heat-fusible elastic fiber, particularly a single covering yarn (hereinafter referred to as SCY) knitted fabric method at 120 ° C. for 20 seconds, particularly at 115 ° C. Efficient and effective by heat-treating a knitted fabric containing a heat-fusible polyurethane elastic fiber having a heat-bonding power of 0.15 cN / dtex or more, preferably 0.3 cN / dtex or more when wet-heat treated for 20 seconds In particular, the inventors have found that a knitted fabric having a shape-retaining function and a run / fray-preventing function, particularly a knitted fabric useful in the clothing field, particularly a molded knitted fabric product field, can be obtained.

That is, the present invention provides a molded knitted fabric having the following shape retention function and run / fray prevention function.
[1] A molded knitted fabric having a shape-retaining function and a run / fray-preventing function, wherein a knitted fabric (excluding an undercarriage knitted fabric) containing heat-fusible elastic fibers is subjected to wet heat treatment.
[2] The molded knitted fabric according to [1], which is formed by a plating knitting using a front yarn made of non-elastic fibers and a back yarn made of heat-fusible elastic fibers.
[3] The molding according to [1], which is formed by a plating knitting using a front yarn made of non-elastic fibers and a back yarn made of composite yarn, and the composite yarn contains heat-fusible elastic fibers. Knitted fabric.
[4] The molded knitted fabric according to [3], wherein the composite yarn is composed of a core yarn made of a heat-fusible elastic fiber and an inelastic fiber covering the core yarn.
[5] The molded knitted fabric according to [4], wherein the composite yarn is a covering yarn, a twisted yarn, or an air entangled yarn.
[6] The molded knitted fabric according to [5], wherein the covering yarn is a single covering yarn.
[7] The heat-sealable elastic fiber is a heat-sealable polyurethane elastic fiber having a heat-seal strength of 0.15 cN / dtex or more when wet-heat treated at 120 ° C. for 20 seconds in the single covering yarn knitted fabric method [1] ] To [6].
[8] The molded knitted fabric according to [7], wherein the heat-fusible polyurethane elastic fiber has a heat-sealing force of 0.30 cN / dtex or more.
[9] The heat-sealable elastic fiber is a heat-sealable polyurethane elastic fiber having a heat-seal strength of 0.15 cN / dtex or more when wet-heat treated at 115 ° C. for 20 seconds in the single covering yarn knitting method [1] ] To [8].
[10] The molded knitted fabric according to [9], wherein the heat-fusible polyurethane elastic fiber has a heat-sealing force of 0.30 cN / dtex or more.
[11] The heat-resistant strength retention when the heat-fusible polyurethane elastic fiber is subjected to a dry heat treatment at 140 ° C. for 45 seconds under double elongation is 40% or more, [7] to [10] Molded knitted fabric.
[12] The molded knitted fabric according to any one of [1] to [11], in which an arbitrary hole is formed or cut into an arbitrary shape.

  According to the present invention, a heat-fusible elastic fiber is heat-sealed in a wet heat treatment (set) step, thereby providing a molded knitted fabric having excellent stretchability and having a shape retention function and a run / fray prevention function. be able to. In particular, it is possible to provide a knitted fabric product in which the knitted fabric is cut by an arbitrary line such as a straight line, a curved line, or a combination of a curved line and a straight line. The shape retention function and the run / fray prevention function occur because the surface of the heat-fusible elastic fiber is melted by wet heat treatment, and the heat-fusible elastic fiber and the heat-fusible elastic fiber and the non-elastic fiber In the case of composite yarns such as SCY, the composite yarns and / or the composite yarns and other fibers are heat-sealed.

  The molded knitted fabric of the present invention is formed by wet heat-treating a knitted fabric containing heat-fusible elastic fibers.

  A configuration example of the molded knitted fabric of the present invention is shown below.

  The form of the heat-fusible elastic fiber used in the knitted fabric of the present invention may be any of raw yarn (unprocessed yarn), false twisted yarn, pre-dyed yarn, etc., and heat-fusible elastic It may be a composite yarn such as a covering yarn in which the periphery is covered with a non-elastic fiber, a twisted yarn in which a heat-fusible elastic fiber and a non-elastic fiber are twisted, and an air entangled yarn. It is preferable to use a covering yarn because the heat-fusible elastic fiber can be arranged at the center of the composite yarn, and the coverage of the heat-fusible elastic fiber can be easily controlled and can be uniformly coated. The covering yarns include SCY (single covering yarn or single covered yarn) or DCY (double covering yarn or double covered yarn). The lower the covering rate of the heat-fusible elastic fiber of the core yarn, the more the heat fusion. SCY is particularly preferable because the number of intersections between the adhesive elastic fibers increases.

  The heat-fusible elastic fiber used in the present invention is not particularly limited as long as it is a heat-fusible elastic fiber that melts by wet heat treatment and exhibits a shape retention function and a run / anti-fraying function. The elastic polyurethane elastic fiber is preferable from the viewpoints of elongation and durability.

  When the heat-sealable polyurethane elastic fiber is used as a SCY for a knitted fabric, the fineness of the heat-sealable polyurethane elastic fiber used for the core yarn is 11 to 470 dtex, preferably 11 to 156 dtex, particularly preferably 11 to 78 dtex, It is preferable from the viewpoint of aesthetics, practicality, and cost that the fineness of the non-elastic fiber is 5.5 to 156 dtex, particularly 8 to 78 dtex.

  In the case of a covering yarn and a twisted yarn, the draft of the polyurethane elastic fiber is preferably 1.0 to 5.5 times, more preferably 1.2 to 5.0 times. The number of twists is preferably 60 to 2500 T / m, more preferably 80 to 2200 T / m, and still more preferably 100 to 2000 T / m. If the number of twists is lower than 60 T / m, the processing stability during knitting on the knitting machine may be lowered. If the number of twists is higher than 2500 T / m, the degree of coverage of the heat-fusible polyurethane elastic fiber of the core yarn is low. It may become high and it becomes difficult to heat-seal | fuse.

  In the case of the air entangled yarn, the draft of the polyurethane elastic fiber is preferably 1.0 to 5.5 times, more preferably 1.2 to 5.0 times. The number of entanglements is preferably 30 to 150 / m, and more preferably 60 to 120 / m. If the number of entanglements is lower than 30 / m, the processing stability during knitting on the knitting machine may be reduced. If the number of entanglements is higher than 150 / m, the degree of coverage of the heat-bonded polyurethane elastic fibers of the core yarn May become difficult to heat-seal.

  Therefore, the number of twists and the number of entanglements need to be changed from time to time depending on the draft (stretch ratio) of polyurethane elastic fibers, the fineness of non-elastic fibers, the average entanglement length, etc. The rate is preferably adjusted to 40% or less, more preferably 35% or less, and still more preferably 30% or less. When the coverage of the heat-sealable polyurethane elastic fiber exceeds 40%, the number of heat-sealable polyurethane elastic fibers between the heat-sealable polyurethane fibers decreases, and the loosely-separated part is easily frayed during repeated use. This is not preferable because the original elongation of the fiber is lost. The coverage as described above is preferable in that it is difficult to fray and curl even when it is repeatedly used as a product in the state of being cut off, and the original elongation of the polyurethane elastic fiber can be exhibited. On the other hand, the coverage is preferably 2% or more from the viewpoint of processing stability during knitting on a knitting machine.

In addition, the coverage of this invention is the value computed by (1) Formula in the case of a covering yarn and a twisted yarn, and (2) Formula in the case of an air entangled yarn.
C = (0.012 × √D × T / (1000 / DR)) × 100 (1) where C is the degree of coverage (%) and D is coated around the heat-sealable polyurethane elastic fiber. T is the number of twisted yarns (T / m) (in the case of double covering yarns, the sum of the upper and lower twisted numbers), and DR is a draft of polyurethane elastic fibers during covering or twisting yarns. Indicates.

C = (K × KL / 1000) × 100 (2) where K is the number of entanglements (pieces / m) during air entanglement, and KL is the average entanglement length (mm).

  On the other hand, the fiber (non-elastic yarn) other than the heat-fusible elastic fiber used in the knitted fabric of the present invention is not particularly limited. For example, natural fibers such as cotton, hemp, wool, silk, rayon, cupra, polynosic Threads made of recycled fibers such as acetate, semi-regenerated fibers such as acetate, chemically synthesized fibers such as nylon, polyester, acrylic, polypropylene, and vinyl chloride can be used.

  In particular, these fibers can be suitably used as non-elastic fibers coated around a heat-sealable polyurethane elastic fiber. In this case, nylon, cotton yarn, rayon, or the like can be typically used as the non-elastic fiber.

  Here, the knitted fabric of the present invention preferably contains 1 to 60% by mass, particularly 2 to 50% by mass of the heat-fusible elastic fiber. If the proportion of the heat-sealing elastic fiber is too small, the heat-sealing force may be reduced, which may cause fraying. If the proportion is too large, the texture of the knitted fabric may be rubbery.

  The knitted fabric of the present invention is a molded knitted fabric containing the above heat-fusible elastic fiber, but the molded knitted fabric refers to a knitted fabric that is knitted into the shape of a product. This includes fully formed knitting (called full fashioning), and semi-formed knitting (called garment-length knitting) that is knitted continuously while separating each length.

Examples of the structure of the molded knitted fabric include the following examples.
(1) The method of weaving a heat-sealable polyurethane elastic fiber alone or a composite yarn containing a heat-sealable polyurethane elastic fiber and a non-elastic fiber is a heat-sealable polyurethane elastic fiber alone or heat-sealing in a stitch. Plating knitting that can adjust and stabilize the position of the composite yarn containing the elastic polyurethane elastic fiber and the non-elastic fiber, and can cross and contact the heat-sealable polyurethane elastic fiber with all the loops is preferable The knitted fabric obtained by knitting the plating can fix all the loops including the heat-sealable polyurethane elastic fibers by heat-seal the heat-sealable polyurethane elastic fibers with each other by heat treatment. Specifically, non-elastic fibers are used as front yarns, and heat-sealable elastic fibers (heat-sealable polyurethane elastic fibers) alone or heat-sealable elastic fibers (heat-sealable polyurethane elastic fibers) as back yarns. A plating knitting using a composite yarn containing

  The heat-sealable polyurethane elastic fiber alone or the composite yarn containing the heat-sealable polyurethane elastic fiber may be used for all courses, or the heat-sealable polyurethane elastic fiber alone and the heat-sealable polyurethane elastic fiber may be used. The composite yarns included may be knitted alternately. Further, the heat-sealable polyurethane elastic fiber alone or the composite yarn containing the heat-sealable polyurethane elastic fiber may be knitted every other course (the heat-sealable polyurethane elastic fiber alone or the heat-sealable polyurethane elastic fiber. It is preferable to use a non-heat-sealable polyurethane elastic fiber alone or a composite yarn containing a non-heat-sealable polyurethane elastic fiber for courses that do not use composite yarn containing It is more preferable to use polyurethane elastic fibers because the tissue can be fixed.

  (2) The present invention can also be used for warp knitted fabrics in which a heat-sealable polyurethane elastic fiber alone or a composite yarn containing a heat-sealable polyurethane elastic fiber and at least one kind of non-elastic yarn are mixed. The knitting structure of warp knitted fabric knitted with a heat-bondable polyurethane elastic fiber alone or a composite yarn containing heat-bondable polyurethane elastic fiber and a non-elastic yarn is a knitted fabric, denvi knitted, cord knitted, atlas knitted, and these Any organization such as a combined or changed organization can be knitted, and all knitting machines such as a tricot knitting machine, a Raschel knitting machine, and a Miranese knitting machine can be used as the knitting machine. Similarly to (1), a heat-sealable polyurethane elastic fiber alone or a composite yarn containing a heat-sealable polyurethane elastic fiber may be knitted, or a heat-sealable polyurethane elastic fiber alone and a heat-sealable polyurethane elastic. A composite yarn containing fibers may be knitted alternately. The heat-sealable polyurethane elastic fiber alone or the composite yarn containing the heat-sealable polyurethane elastic fiber may be either inserted or knitted.

  In addition, the knitted fabric production conditions (count number, elongation dimension, etc.) can also be produced under known conditions by normal molding knitting.

  The knitted fabric obtained above is usually preset in order to stabilize the stitches and dimensions, but is wet-heated at 80 ° C. for about 30 minutes. After the presetting, when the product is formed of a molded knitted fabric of each part, each molded knitted fabric is sewn with a sewing machine as necessary to obtain a shape of the knitted fabric product. Furthermore, a dyeing process etc. are given as needed. These can be performed under known conditions and processes.

After presetting, wet heat setting is performed. The wet heat setting method uses, for example, a steam setter manufactured by Iwata Mfg. Co., Ltd., and the steam valve is opened at a steam source pressure of 2.5 to 3.0 kg / cm ² . Then, steam is put into a sealed set chamber, and the set chamber is controlled to a predetermined temperature. In this case, the set temperature is 80 to 140 ° C, particularly 90 to 135 ° C. Next, the knitted fabric is attached to the template, placed in the set chamber, and set for a predetermined time. The set time can be 10 to 180 seconds, in particular 15 to 120 seconds. Then, it puts into a drying chamber with a dry heat of 110 ° C. and dries for 60 seconds. The setting machine that performs the wet heat setting is not particularly limited as long as the wet heat setting can be performed at the set temperature and the set time.

  When the wet heat setting (treatment) temperature is too low, or when the time is too short, there is a possibility that the heat fusion force or setting effect is insufficient, the fraying prevention function, the dimensional stability of the knitted fabric may be inferior, and if it is too high, Alternatively, if the time is too long, there is a risk that adverse effects such as a decrease in strength of the non-elastic fiber, thermal discoloration, a hard texture, and poor shrinkage characteristics may occur.

  In the present invention, the heat-sealable polyurethane elastic fibers are melted by this wet heat setting treatment, and the heat-sealable elastic fibers and / or the intersections between the heat-sealable elastic fibers and the non-elastic fibers are heat-sealed. In the case of a covering yarn, the heat-fusible elastic fiber and the non-elastic fiber covering the heat-fusible elastic fiber are heat-sealed, and at the intersection of the knitted fabric, the heat-fusible property intersects. A composite yarn in which an elastic fiber or a heat-fusible elastic fiber is used as a core yarn and the periphery thereof is coated with a non-elastic fiber and / or the non-elastic fiber is heat-sealed.

  Here, in the present invention, the heat-sealable elastic fiber is a heat-sealable elastic fiber or a heat-sealable elastic fiber and / or a heat-sealable elastic fiber and other heat-sensitive elastic fiber. A state in which the non-elastic fibers are fused and in close contact, a state in which at least a part of the fibers are fused and in close contact, or a state in which the fibers are adhered to each other even without reaching the fusion. .

  The heat-fusible polyurethane elastic fiber used in the present invention will be described in more detail. As the heat-fusible polyurethane elastic fiber, when the heat-sealing force in the SCY knitted fabric method is wet-heat treated at 120 ° C. for 20 seconds, 0.15 cN / dtex or more is preferable, and it is particularly preferable that the heat-sealing force when wet-heat-treated at 115 ° C. for 20 seconds is 0.15 cN / dtex or more. Furthermore, it is preferable that the heat fusion force when wet-heat treated at 120 ° C. for 20 seconds is 0.30 cN / dtex or more, and particularly the heat fusion force when wet-heat treated at 115 ° C. for 20 seconds is 0.30 cN / dtex. Even more preferred.

  As for the heat fusion force, the actual effect may not be observed when the heat fusion force in the SCY knitted fabric method is less than 0.15 cN / dtex, but if it is 0.15 cN / dtex or more and less than 0.3 cN / dtex, it is a disposable product. There is a certain effect in preventing wire and run. If it is 0.30 cN / dtex or more, wire transmission prevention is more effective, and even if the knitted fabric is damaged, wire transmission prevention is effective. Resistance to wire transmission and durability against fraying is proportional to the heat fusion force. Get higher. However, if moist heat treatment is strengthened to increase the heat-sealing power, the shared fiber may become harder and the texture may decrease, and appropriate conditions for appropriate heat-sealing power and the original texture of the fiber used will be selected. It is desirable.

  Therefore, as a more balanced condition in terms of performance and texture, the heat-sealing power when wet-heat treated at 120 ° C. for 20 seconds is preferably 0.30 cN / dtex or more, and in particular, the heat when wet-heat treated at 115 ° C. for 20 seconds. The fusion power is preferably 0.30 cN / dtex.

  The reason why a large heat-sealing effect can be obtained by using the polyurethane elastic fiber of the present invention is that the surface of the polyurethane elastic fiber is easily softened even by wet heat, and the contact points between the elastic fibers are fused together. It can be considered that the common fiber used together with the fiber is also fused.

Here, in the present invention, the SCY knitted fabric method refers to the following method.
(1) SCY covered with polyurethane elastic fibers 11 to 156 dtex as a core yarn, nylon 6 filament yarn 13 dtex 5 filament (trade name Amilan manufactured by Toray Industries, Inc.) as a covering yarn, and draft ratio 2.3 times and twist number 600 T / M Is made.
(2) The SCY produced in (1) is fed to the yarn feeder of the pantyhose knitting machine (Lonati L416 / R, hook diameter: 4 inches, number of needles 400), the count is 2400 course, the elongation is 45 cm, A pantyhose knitted fabric is produced with only one SCY bite.
(3) After the toes of the pantyhose knitted fabric are sewn with a sewing machine, the pantyhose knitted fabric is put into an aluminum template having a width of 11 cm and stretched 1.2 times in the well direction, and heat-treated at a predetermined temperature for 20 seconds with a wet heat setting machine (Heat set).
(4) The heat sealing force is measured by the following method.
Tensile tester [Shimadzu Seisakusho precision universal testing machine] SCY disassembled from the end of the knitted fabric gripped by the upper chuck is gripped by the lower chuck under a load of 0.1 cN, and the grip interval (chuck interval) is 100 mm. Pulling is performed at a pulling speed of 100 mm / min, and the tension when the SCY is knitted from the knitted fabric is measured.
Next, about the peak point of the deknitting tension measured every time the heat fusion part dissociates,
The peak average knitting tension is obtained by averaging the third peak point having a large value between the elongation of 100 mm and 200 mm at which the knitting stress is stabilized. Subsequently, the peak average knitting tension (cN) is divided by the initial fineness (dtex) of the polyurethane elastic fiber to obtain a heat fusion force (cN / dtex).

  When the thermal fusion between the polyurethane elastic fibers or between the polyurethane elastic fibers and the used nylon is increased, the SCY deknitting tension is increased. When the heat fusion further proceeds, the polyurethane elastic yarn in the gripped SCY breaks due to elongation, and only the nylon remaining in the gripping portion is pulled out. This indicates that the heat fusion force has reached the maximum.

The heat-sealable polyurethane elastic fiber used in the present invention preferably further has the following physical properties.
That is, it is preferable that the value of the heat-resistant strength retention rate when dry-heat-treated at 150 ° C. for 45 seconds under double elongation is 20% or more, particularly 30% or more. If the heat resistant strength retention is less than 20%, even if there is a run or fraying prevention effect, the stretch recovery property of the polyurethane elastic fiber is lowered or the physical properties are lowered, which is not preferable. The upper limit of the heat resistant strength retention is not particularly limited, but is usually 110% or less, particularly 100% or less.

  Further, when the polyurethane elastic fiber used in the present invention is subjected to a dry heat treatment at 140 ° C. for 45 seconds, the heat resistant strength retention value is preferably 40% or more, particularly preferably 50% or more, and a dry heat treatment at 150 ° C. for 45 seconds. More preferably, the strength retention is 20% or more, and the strength retention when subjected to a dry heat treatment at 140 ° C. for 45 seconds is 40% or more.

The heat resistant and strong retention rate is determined by the following measurement method.
The polyurethane elastic fiber is held at a grip length of 8 cm and stretched to 16 cm. It is put into a hot air drier maintained at a predetermined temperature in a stretched state for 45 seconds to perform a dry heat treatment. The strength at break of the polyurethane elastic fiber after the heat treatment is measured at a grasping length of 5 cm and an elongation rate of 500 m / min using a constant elongation tensile tester. The measurement environment is a temperature of 20 ° C. and a relative humidity of 65%. Displays the heat resistant strength retention rate for the fiber before heat treatment.

  Moreover, when the polyurethane elastic fiber used in the present invention is subjected to a dry heat treatment at 140 ° C. for 45 seconds, the value of the heat set rate is preferably 30% or more, particularly preferably 40% or more. It is preferable that the heat set rate when dry-heat-treated at 150 ° C. for 45 seconds is 50% or more. If the heat setting rate is too small, the dimensions during processing are unstable and wrinkles may remain on the knitted fabric, which is not preferable. The upper limit of the heat setting rate is not particularly limited, but is usually 100% or less, particularly 90% or less.

The method for measuring the heat set rate is as follows.
The polyurethane elastic fiber is held at a grip length of 8 cm and stretched to 16 cm. It is put into a hot air drier maintained at a predetermined temperature in a stretched state for 45 seconds to perform a dry heat treatment. After 30 seconds from the end of the heat treatment, the grasping length is narrowed to 4 cm so that the yarn is loosened. After 5 minutes and 30 seconds from the end of the heat treatment, the grasping length is increased, and after slightly extending, the grasping length is reduced by 1 mm. Pay attention to the whole yarn and measure the length where the yarn begins to loosen. The measurement environment is a temperature of 20 ° C. and a relative humidity of 65%.
Obtain the heat set rate using the following formula.
Heat setting rate (%) = [(16 cm−measured value cm) / 8 cm] × 100

  Further, the polyurethane elastic fiber used in the present invention preferably has a residual strain immediately after stretching by 300% of 40% or less, particularly 35% or less. A product using a polyurethane elastic fiber having a residual strain of more than 40% is not preferable because problems such as elbow slipping, knee slipping, and full stretch occur, and the correction effect of the body is not sufficiently exhibited.

Residual strain immediately after 300% elongation refers to the residual strain when the stress becomes zero when the original length is recovered at the same speed as at the time of stretching immediately after stretching to 16 cm at a grasping length of 4 cm and 300 mm / min. A value calculated from the following formula based on elongation.
Residual strain = (residual elongation, cm / 4) x 100 (%)

  The method for producing the heat-fusible polyurethane elastic fiber used in the present invention is not particularly limited as long as the heat-fusible polyurethane elastic fiber having the above characteristics is obtained. The melt spinning method and the dry spinning method are not particularly limited. Any of these may be adopted.

  For example, a polyol and an excess molar amount of diisocyanate are reacted to produce a polyurethane intermediate polymer having isocyanate groups at both ends, and a low molecular weight diamine having an active hydrogen that can easily react with the isocyanate group of the intermediate polymer. A polyurethane solution (polymer solution) is produced by reacting a molecular weight diol in an inert organic solvent, and then the solvent is removed to form a yarn, or a polyol, a diisocyanate, a low molecular weight diamine or a low molecular weight diol. A method in which the reacted polymer is solidified and dissolved in a solvent, and then the solvent is removed and formed into a yarn; a method in which the solidified polymer is formed into a yarn by heating without dissolving in the solvent; and the polyol and Reacting diisocyanate with low molecular weight diol to obtain a polymer and solidifying the polymer Method of forming a Ku yarn, furthermore, after mixing the polymer or polymer solution obtained in each of the above methods, the solvent was removed from the mixed polymer solution, and a method of forming the yarn.

The method for obtaining the polyurethane elastic fiber of the present invention by the melt spinning method is not particularly limited. For example, the following three methods are known.
(1) A method of melt spinning a polyurethane elastic chip.
(2) A method of spinning a polyurethane elastic chip after mixing a polyisocyanate compound.
(3) A reactive spinning method in which a spinning polymer obtained by reacting a prepolymer obtained by reacting a polyol and diisocyanate with a low molecular weight diol is synthesized and then spun without solidification.

  The method (3) is simpler than the methods (1) and (2) because there is no process for handling the polyurethane elastic chip, and the injection rate of the prepolymer into the reactor is adjusted to perform spinning. This is a preferred method because the amount of residual isocyanate groups in the subsequent polyurethane elastic fiber can be adjusted, and heat resistance can be improved by a chain extension reaction with the residual isocyanate groups. Furthermore, in the method (3), as disclosed in JP-A-11-39030, a low molecular weight diol is reacted in advance with a part of the prepolymer and injected into the reactor as a prepolymer having an excess of hydroxyl groups. You can also do it.

  More specifically, (I) a both-end isocyanate group prepolymer obtained by reacting a first polyol and a diisocyanate (hereinafter referred to as “both-end isocyanate group prepolymer”), (II) a second polyol, a diisocyanate, and It is possible to suitably employ a method of melt spinning without solidifying a polymer obtained by reacting a hydroxyl group prepolymer obtained by reacting a low molecular weight diol (hereinafter referred to as “both hydroxyl group prepolymer”). it can.

  In this case, the spinning polymer is synthesized by (I) synthesizing a prepolymer having a terminal isocyanate group obtained by reacting a first polyol having a number average molecular weight of 800 to 3,500 with a diisocyanate, and (II) a number average molecular weight of 600. Synthesis of both-terminal hydroxyl group prepolymers obtained by reacting ˜3,000 second polyols, diisocyanates and low molecular weight diols, and (III) spinning by continuously introducing these two prepolymers into a reactor. It consists of three reactions for the synthesis of polymers for use.

  When the heat-fusible polyurethane elastic fiber of the present invention is produced by the melt spinning method, the number average molecular weight of the first polyol is preferably about 800 to 3,500, and the number average molecular weight of the second polyol is preferably used. Is preferably about 600 to 3,000 polymer diol.

  If the number average molecular weight of the first polyol is smaller than this range, the elongation at break and elastic recovery of the resulting polyurethane elastic fiber may decrease, and if larger, the break strength, heat resistance, cold resistance, etc. may decrease, The extrudability at the time of spinning, for example, in the case of melt spinning, may decrease the spinnability. Therefore, more preferably, the number average molecular weight of the first polyol is about 1,000 to 3,000.

  On the other hand, if the number average molecular weight of the second polyol is smaller than this range, the yarn may become hard or lack homogeneity, and if it is large, the heat resistance and strength improvement effects may not be expected. More preferably, the number average molecular weight of the second polyol is about 800 to 2,500.

  When the second polyol has a lower molecular weight than the molecular weight of the first polyol, it is preferable in view of physical properties such as an increase in yarn strength. In addition, the measuring method of the number average molecular weight of a polyol can be calculated from a hydroxyl value according to JIS K1557.

  As the polyol that can be used in the heat-fusible polyurethane elastic fiber of the present invention, polyether glycol, polyester glycol, polycarbonate glycol, or the like can be used.

  Examples of the polyether glycol include polyether diols obtained by ring-opening polymerization of cyclic ethers such as ethylene oxide, propylene oxide, and tetrahydrofuran; ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, neo Modified PTMG, THF and 2 which are copolymers of polyether glycol, THF and 3-MeTHF obtained by polycondensation of glycols such as pentyl glycol, 1,6-hexanediol and 3-methyl-1,5-pentanediol And modified PTMG which is a copolymer of 3-dimethylTHF.

  Examples of the polyester glycol include glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, and 3-methyl-1,5-pentanediol. Polyester glycol obtained by polycondensation of at least one selected from the group with at least one selected from dibasic acids such as adipic acid, sebacic acid, and azelaic acid; opening of lactones such as ε-caprolactone and valerolactone Examples thereof include polyester glycol obtained by ring polymerization.

  Examples of the polycarbonate glycol include dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; alkylene carbonates such as ethylene carbonate and propylene carbonate; at least one organic carbonate selected from diaryl carbonates such as diphenyl carbonate and dinaphthyl carbonate; and ethylene glycol. At least one aliphatic diol selected from propylene glycol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and the like And carbonate glycol obtained by the transesterification reaction.

  The polyether glycols, polyester glycols, and polycarbonate glycols exemplified above can be used singly or in combination of two or more, but preferably contains a polyester diol.

  Next, as the diisocyanate that can be used in the production of the heat-fusible polyurethane elastic fiber by the melt spinning method of the present invention, aliphatic, alicyclic, aromatic, and aromatic fats that are usually used in the production of polyurethane are used. Arbitrary diisocyanate can be used.

  Examples of such diisocyanates include 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene. Diisocyanate, p-phenylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, meta-tetramethylxylene diisocyanate, para-tetramethylxylene diisocyanate, etc. may be used, and one of these may be used alone or in combination of two or more. Among these, 4,4′-diphenylmethane diisocyanate and 4,4′-dicyclohexylmethane diisocyanate are preferably used.

  As the chain extender, low molecular weight diols and low molecular weight diamines can be used, those having an appropriate reaction rate and giving appropriate heat resistance, and at least two which can react with isocyanate in the molecule. A low molecular weight compound having an active hydrogen atom and generally having a molecular weight of 500 or less is used.

  Examples of the low molecular weight diol that can be used in the heat-fusible polyurethane elastic fiber of the present invention include diols having 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, neo Aliphatic diols such as pentyl glycol, 1,6-hexanediol, and 3-methyl-1,5-pentanediol can be used. These can be used individually by 1 type or in combination of 2 or more types.

  In the present invention, in particular, a diol having 2 and / or 4 carbon atoms and at least one low molecular weight diol selected from diols having 3, 5 and 6 carbon atoms, a diol having 6 carbon atoms, and a carbon number Combining at least two low molecular weight diols in combination with 3 and / or 5 diols is preferable from the viewpoints of excellent heat-sealing effect and reactivity, spinning stability, physical properties and the like. In the above, as the low molecular weight diol having 2 to 6 carbon atoms, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol should be used. Is preferred.

  A low molecular weight diol and a low molecular weight diamine can be used in combination, but in the method for producing a heat-fusible polyurethane elastic fiber by the melt spinning method of the present invention, a low molecular weight diol may be more preferably used as a chain length extender. it can.

  Moreover, monofunctional monools, such as butanol, and monofunctional monoamines, such as diethylamine and dibutylamine, can also be mixed and used as a reaction regulator or a polymerization degree regulator.

  Further, the active hydrogen compound having an average functional group number (number of active hydrogen atoms in the molecule) having a functional group such as a hydroxyl group and / or an amino group of 3 to 6, particularly 3 or 4, within a range not inhibiting the spinnability. Can be used. Examples of such compounds include glycerin, trimethylolethane, trimethylolpropane, hexanetriol, pentaerythritol (tetravalent), sorbose (pentavalent), sorbitol (hexavalent), 1,3,5-triaminobenzene. Etc.

  In this case, if the number of functional groups exceeds 6, it is not preferable because the elasticity (flexibility) of the finally obtained polyurethane cannot be imparted. Trifunctional compounds are preferably used, and glycerin, trimethylolethane, and trimethylolpropane are particularly preferably used.

  The amount of the active hydrogen compound used is preferably such that the trifunctional compound is within 6 equivalent% with respect to the total of the chain extender and the active hydrogen compound. If it exceeds 6 equivalent%, flexibility cannot be imparted and spinnability is not stable, which is not preferred. Particularly preferred is 4 equivalent% or less.

  Optional components such as an ultraviolet absorber, an antioxidant, and a light stabilizer can be added to the heat-fusible polyurethane elastic fiber of the present invention in order to improve weather resistance, heat oxidation resistance, and yellowing resistance. When using a stabilizer, heat resistance and yellowing resistance vary greatly depending on the type and amount of the stabilizer, so select the type of stabilizer that is effective against the polyurethane polymer, and each is effective. It is preferable to use a combination of stabilizers in combination. By using suitable stability, it is possible to obtain a polyurethane elastic fiber which is hardly yellowed and has excellent heat resistance.

  Other stabilizers such as semicarbazide compounds, organic sulfur secondary antioxidants such as bisphenol S, phosphite secondary antioxidants, barium sulfate, magnesium oxide, magnesium silicate, calcium silicate, zinc oxide as required , Inorganic fine particles such as hydrotalcite, titanium oxide, zirconium-containing compounds, anti-adhesive agents such as magnesium stearate, calcium stearate, polytetrafluoroethylene, organosiloxane, antistatic agents such as fluorine or siloxane, colloidal Inorganic colloidal sols such as silica or colloidal alumina, silane coupling agents, thermal fusion improvers such as phosphate esters, phosphite esters, pyrophosphate esters, preservatives such as methyl paraoxybenzoate and ethyl paraoxybenzoate, etc. Colorant, fungicide, defoaming agent, plasticizer, waxes, softeners, mold release agents, foaming agents, fillers, nucleating agent, antibacterial agents, deodorants, anti-blocking agents.

  The composition ratio of the raw materials is preferably 0.95 to 1.25, more preferably the molar ratio of the molar amount of all diisocyanates to the total molar amount of all polyols and all low molecular weight diols. 1.005 to 1.205.

  The molar ratio of all diisocyanates and polyol (total of the first polyol and the second polyol) is preferably 2.4 to 3.8, and more preferably 2.5 to 3.5. If the molar ratio is lower than 2.4, the resulting polyurethane elastic fiber has high elongation, but heat resistance may be insufficient. If the molar ratio is higher than 3.8, the heat resistance is good, but the yarn is hard and stretched. May be lower.

  The heat-fusible polyurethane elastic fiber of the present invention comprises (1) the kind and content of polyol, and (2) the kind and content of low molecular weight diol, and the nitrogen content contained in the polyurethane fiber immediately after spinning. By adjusting and combining, high heat-fusibility can be achieved. Specifically, the above conditions (1) and (2) are further divided into the following conditions.

(1a) When the proportion of the polyester polyol component in the total polyol (total of the first and second polyols) is 55 mol% or more and 95 mol% or less.
(1b) When the proportion of the polyether polyol component in the total polyol is 60 mol% or more and 100 mol% or less.
(2a) The proportion of the diol having 2 to 6 carbon atoms in the total low molecular weight diol is 55 mol% or more and less than 80 mol%, and the nitrogen content of the polyurethane fiber immediately after spinning is 2.8 mass% or more. When the content is 4.2% by mass or less.
(2b) The proportion of the diol having 2 to 6 carbon atoms in the total low molecular weight diol is 80 mol% or more and less than 98 mol%, and the nitrogen content of the polyurethane fiber immediately after spinning is 2.2 mass% or more. When 2% by mass or less.
(2c) The ratio of the diol having 2 to 6 carbon atoms in the total low molecular weight diol is 98 mol% or more and 100 mol% or less, and the nitrogen content of the polyurethane fiber immediately after spinning is 2.2 mass% or more. When less than 8% by mass.

  In the present invention, the main low molecular weight diol refers to a low molecular weight diol having the largest molar amount (55 mol% or more) among all low molecular weight diols.

  Explaining each condition, first, as to the type and content of the polyol, (1a) In order to obtain particularly good fusing property and the degree of uniformity of the knitted fabric, the polyester polyol component in the total polyol is 55 mol% or more. Preferably, it is 55 mol% or more and 95 mol% or less, and more preferably 60 mol% or more and 90 mol% or less. If the proportion of the polyester polyol is too small, the spinnability and yarn uniformity may be lowered or the chlorine resistance may be inferior, and if it is too large, the alkali resistance and mold resistance may be inferior. In addition, it is preferable to select a polyester polyol component as the first polyol from the viewpoint of increasing the degree of yarn uniformity.

  On the other hand, (1b) In order to obtain particularly good fusing property and high heat-resistant strength retention, the polyether polyol component in the total polyol is 60 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol%. It is desirable that it is not more than mol%. If the proportion of the polyether polyol is too small, the heat-resistant strength retention rate may decrease, and the spinnability and yarn uniformity may decrease. In addition, it is preferable from a point of alkali resistance that a 1st polyol consists of a polyether polyol component.

  Next, regarding the type and content of the low molecular weight diol, (2a) the content of the main diol having 2 to 6 carbon atoms is 55 mol% or more and less than 80 mol% with respect to the total low molecular weight diol. Is more preferable, and more preferably 60 mol% or more and less than 80 mol%. Among the diols having 2 to 6 carbon atoms, the diol having 2 to 6 carbon atoms, which is the main low molecular weight diol, has a poor fiber elongation recovery rate and compression set when the combined amount is less than 55 mol%. There is a case.

  When the content of the diol having 2 to 6 carbon atoms is 55 mol% or more and less than 80 mol%, the nitrogen content of the obtained polyurethane elastic fiber is 2.8 mass% or more and 4.2 mass% or less, particularly 2.8 mass%. % To 3.4% by mass is preferable. If the nitrogen content is too low, the heat resistance may be low, and if it is too high, the heat-sealing force may be low.

  On the other hand, when the content of the diol having 2 to 6 carbon atoms is 80 mol% or more and less than 98 mol%, the nitrogen content is 2.2 mass% or more and 4.2 mass% or less, particularly 2.6 mass%. % Or more and 3.4% by mass or less is preferable. If the nitrogen content is too low, the concentration of bonds involved in the reaction with the isocyanate is lowered, and heat resistance and wear resistance are inferior, which is not preferable. If the nitrogen content is too high, the hardness in the polyurethane caused by the isocyanate compound In some cases, the cohesive strength of the segments becomes strong and the elastic recovery rate is poor.

  Here, in the present invention, it is preferable to use at least two kinds of low molecular weight diols among the diols having 2 to 6 carbon atoms as described above, but in the case of (2a) and (2b), the number of carbon atoms is 2 And / or 4 diol and at least one low molecular weight diol selected from diols having 3, 5 and 6 carbon atoms are used in combination from the viewpoint of heat resistance, elongation recovery property, etc. Or a diol having 4 diols is preferred, and when a diol having 6 carbon atoms and a diol having 3 and / or 5 carbon atoms are used in combination, heat resistance, elongation recovery property, stretching fatigue resistance, chemical resistance From such points, it is preferable that the diol having 6 carbon atoms is mainly used.

  (2c) When the content of the diol having 2 to 6 carbon atoms is 98 mol% or more and 100 mol or less, the nitrogen content is 2.2 mass% or more and less than 2.8 mass%, particularly 2.4 mass%. The content is preferably less than 2.8% by mass. If the nitrogen content is too low, the concentration of bonds involved in the reaction with the isocyanate is lowered, and heat resistance and wear resistance are inferior, which is not preferable. If the nitrogen content is too high, the hardness in the polyurethane caused by the isocyanate compound In some cases, the cohesive strength of the segments becomes strong and the thermal fusion force becomes low.

  In the case of (2c), at least one low molecular weight diol among the diols having 2 to 6 carbon atoms can be used, and the diols having 2, 4 and 6 carbon atoms from the viewpoint of heat resistance, elongation recovery property and the like. It is preferable that at least one low molecular weight diol selected from is mainly used.

  In the present invention, polyurethane elastic fibers excellent in heat-fusibility are obtained by a method combining the above (1a) or (1b) and the conditions (2a), (2b) or (2c). And can produce unique effects as described above under each condition.

  In the present invention, when carrying out cotton refining / bleaching processing, etc., it is preferable from the viewpoint of alkali resistance and the like to use a polyurethane elastic fiber containing a large amount of a polyether polyol component produced under the condition (1b). .

  The melt spinning method will be described more specifically. The both-end isocyanate group prepolymer (I) is prepared by, for example, charging a predetermined amount of diisocyanate into a tank equipped with a hot water jacket and a stirrer and then stirring the predetermined amount of polyol. And stirred at 60 to 130 ° C. for 30 to 100 minutes, more preferably at 80 to 120 ° C. for 50 to 70 minutes under a nitrogen purge.

  When the reaction temperature is less than 60 ° C., the reaction time is significantly increased, and in some cases, the prepolymer may be precipitated. Moreover, when reaction temperature exceeds 130 degreeC, side reactions, such as a dimer of an isocyanate group, and a trimerization reaction, will become remarkable and is unpreferable.

  Both-end isocyanate group prepolymers obtained by this reaction are injected into a polyurethane elastic fiber reactor using a jacketed gear pump (for example, KAP-1 manufactured by Kawasaki Heavy Industries, Ltd.).

  (II) The both-terminal hydroxyl group prepolymer is prepared by charging a predetermined amount of diisocyanate into a tank equipped with a warm water jacket and a stirrer, and then injecting a predetermined amount of polyol while stirring, at 30 to 100 ° C. for 30 to 100 minutes. The precursor can be obtained by stirring under a nitrogen purge, preferably at 80 to 120 ° C. for 50 to 70 minutes, and then the low molecular weight diol can be injected and stirred to react with the precursor. When the reaction temperature is 80 ° C. or lower, the reaction time is significantly increased, and in some cases, a prepolymer is precipitated. On the other hand, when the reaction temperature is 130 ° C. or higher, side reactions such as dimer and trimerization reaction of isocyanate groups become remarkable.

  The obtained both-end hydroxyl group prepolymer is injected into a polyurethane elastic fiber reactor using a jacketed gear pump (for example, KAP-1 manufactured by Kawasaki Heavy Industries, Ltd.). In addition, the above-mentioned various chemicals for improving weather resistance, heat oxidation resistance, yellowing resistance and the like can be added during or after the synthesis of both prepolymers (I) and (II).

  Synthesis of the spinning polymer (III) can be obtained by continuously reacting the prepolymers (I) and (II) fed at a constant ratio. In this case, the reactor may be one that is used in the usual melt spinning method of polyurethane elastic fibers, and is equipped with a mechanism that heats, stirs and reacts the spinning polymer in a molten state, and further transports it to the spinning head. Is preferred.

  The reaction conditions are 160 to 220 ° C. for 1 to 90 minutes, preferably 180 to 210 ° C. for 3 to 80 minutes. When the reaction temperature is less than 160 ° C, the prepolymers (I) and (II) are in a highly viscous state, so that the uniform mixing reaction cannot be performed. When the reaction temperature is 220 ° C or more, the spinning polymer is yellowed by heat. Or undesirably deteriorated.

  When the raw material is directly fed into the reactor for continuous production, a local reaction occurs in the screw, barrel, or polymer flow path, so that bis (hydroxyphenyl) s can be added to the prepolymer. Since this bis (hydroxyphenyl) does not react locally and can be polymerized under uniform kneading, as described in “Polyurethane composition” of JP-A-8-176254, it is difficult to generate scale and process stability. Highly reliable polyurethane can be supplied.

  By using these bis (hydroxyphenyl) s alone or in combination of two or more, polyurethane elastic fibers with excellent transparency and excellent physical properties such as high elongation and heat resistance. Is obtained. Preferred bis (hydroxyphenyl) s are bis (4-hydroxyphenyl) sulfone, bisphenol A, 3,3′-dimethyl-4,4′-dihydroxyphenylsulfone, 3,3 ′, 5,5′-tetramethyl- 4,4′-dihydroxyphenylsulfone and the like can be mentioned.

The heat-sealable polyurethane elastic fiber by the melt spinning method of the present invention can be obtained by transferring the synthesized spinning polymer to the spinning head without solidifying, and discharging and spinning from the nozzle. The average residence time in the reactor varies depending on the type of the reactor, and is calculated by the following equation.
Average residence time in reactor = (reactor volume / spinning polymer discharge rate) x specific gravity of spinning polymer

  The average residence time of the spinning polymer in the reactor is generally about 20 to 180 minutes when a cylindrical reactor is used, more preferably about 30 to 120 minutes, and 30 when a twin screw extruder is used. Second to 30 minutes, more preferably 1 to 20 minutes. The spinning temperature is preferably 160 to 230 ° C., more preferably 180 to 220 ° C., and it can be obtained by continuously extruding from a nozzle, cooling, attaching a spinning oil agent and winding.

  When the spinning temperature is less than 160 ° C., the spinning polymer causes an ejection failure from the nozzle, which is not preferable, and when the spinning temperature is 230 ° C. or higher, the spinning polymer undergoes a decomposition reaction.

  Here, the ratio of the both-end isocyanate group prepolymer and the both-end hydroxyl group prepolymer is such that the residual isocyanate group (residual NCO%) in the yarn immediately after spinning is 0.2 to 1.0 mass%, more preferably 0. It is preferable to adjust the rotation ratio of the injection gear pump as appropriate so that it remains at 25 to 0.90 mass%. When the residual isocyanate group is contained in an excess of 0.2% by mass or more, physical properties such as high elongation and heat resistance can be improved by a chain extension reaction after spinning. However, if the residual isocyanate group is less than 0.2% by mass, the heat resistance of the resulting polyurethane elastic fiber may be lowered, and if it exceeds 1.0% by mass, the viscosity of the spinning polymer is lowered, and spinning is performed. May become difficult. Moreover, there is a possibility that defects such as the melting point of the spun yarn becomes too high.

The content of residual isocyanate groups in the spun fiber is measured as follows.
After the spun fiber (about 1 g) was dissolved in a dibutylamine / dimethylformamide / toluene solution, excess dibutylamine was reacted with residual isocyanate groups in the sample, and the remaining dibutylamine was titrated with hydrochloric acid to remove residual isocyanate groups. Calculate the content.

  In order to perform spinning while leaving the residual isocyanate group, it is preferable to apply an oil agent during spinning. When spinning without applying an oil agent, there are cases where residual isocyanate groups react after spinning and the yarns adhere to each other, and the unwinding property may deteriorate.

  Examples of the components of the base oil used in the present invention include mineral oil and silicone oil.

  The oil agent is preferably applied so that the oil agent is contained in the polyurethane elastic fiber in an amount of 1 to 10% by mass, particularly 2 to 8% by mass. The above value is referred to as the ratio of the oil agent applied to the polyurethane elastic fiber, that is, the application ratio, which is a ratio of both the content ratio (the ratio included) and the adhesion ratio (the ratio applied). .

  If the oil agent is less than 1% by mass with respect to the polyurethane elastic fiber, the unwinding property is poor and wear due to metal such as a knitting needle is liable to occur, and it is not preferable, and if it exceeds 10% by mass, the paper tube A lot of oil agent adheres to the inner layer part of the yarn wound around the inner layer, the inner layer polymer deteriorates due to the oil agent, nozzle debris is generated, and when non-elastic fibers and knitted fabric are created, oligomers of inelastic fibers are precipitated, etc. Unfavorable because it adversely affects.

  The application rate can be measured by gravimetric method or petroleum ether extraction method. The measurement method based on the gravimetric method measures the mass of the empty paper tube, the amount of polymer discharged from the spinning nozzle per unit time, the winding time of the yarn around the paper tube, and the mass of the wound body in advance. The remaining mass obtained by subtracting the total amount of polymer discharged and the mass of the empty paper tube from the mass of the oil is the amount of oil applied, and the ratio obtained by dividing the total amount of polymer discharged from the amount of oil obtained by calculation is the amount of oil applied. Rate.

The measuring method by petroleum ether extraction method is
(1) About 2 g of the wound yarn sample (A) is precisely weighed and then washed with 50 ml of petroleum ether for 1 minute.
(2) After this washing is repeated three times, the wound yarn sample is sandwiched between filter papers and sufficiently dried.
(3) After air drying at room temperature, the weight (B) of the wound yarn sample is measured. OPU is calculated according to the following formula.
OPU (amount of oil applied)% = {(A−B) / (B)} × 100
In simple terms, the OPU% can be obtained by the gravimetric method and by any method of the petroleum ether extraction method as a confirmation test.

  The yarn wound with the oil agent is subjected to solid phase polymerization to complete the reaction.

  As described above, the polyurethane elastic fiber of the present invention preferably has a residual isocyanate group in the yarn immediately after spinning of 0.2 to 1.0% by mass, but the residual isocyanate group is less than 0.2% by mass. In this case, since the amount of cross-linking is small, the heat resistance is low and the yarn is easily broken. On the other hand, if the residual isocyanate group exceeds 1.0% by mass, the amount of cross-linking is increased and the heat resistance increases, so that it takes time to melt and it is difficult to obtain heat-fusibility, which is not preferable.

  By setting it as the said range, the effect of favorable heat-fusion property can be acquired by wet heat processing, maintaining heat resistance required as a polyurethane elastic fiber.

  The polyurethane elastic fiber obtained by the above production method has a heat fusion strength of 0.15 cN / dtex or more, preferably 0.30 cN / dtex when wet-heat treated at 120 ° C. for 20 seconds, particularly 115 ° C. for 20 seconds in the SCY knitting method. Since it is the above, the shaping | molding knitted fabric which suppressed generation | occurrence | production of fraying etc. can be obtained by carrying out the wet heat processing of the shaping | molding knitted fabric containing this heat-fusible polyurethane elastic fiber.

  The molded knitted fabric of the present invention can be used as various molded knitted fabric products such as ladies' underwear such as gentleman / woman inner, sports inner and outer, shorts, and lingerie. Depending on the preference of consumers, such as consumers, products such as clothing can be cut and used, or a part of the product can be cut out in any shape such as a circle, diamond, heart, star shape, etc. It can also be used in a fashioned state.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not restrict | limited to the following Example.

[Example 1] Production of polyurethane elastic fiber by melt spinning method (with low molecular weight diol second component)
23.5 parts of 4,4'-diphenylmethane diisocyanate (MDI) as a synthetic diisocyanate for both-terminal hydroxyl group prepolymer was charged into a reactor equipped with a warm water jacket at 80 ° C. sealed with nitrogen gas, and the number average molecular weight was used as a polymer diol. 48.1 parts of 1,000 polytetramethylene ether glycol (PTMG) was injected with stirring and allowed to react for 1 hour. Next, 18.2 parts of 1,4-butanediol (BDO) was injected as a low molecular weight diol and allowed to react for 1 hour. Further, 10.2 parts of 1,6-hexanediol (HDO) and 1.0 part of bis (4-hydroxyphenyl) sulfone (BHPS) were added and stirred for 15 minutes to synthesize a hydroxyl group prepolymer at both ends.

In parallel with this, 29.6 parts of MDI as diisocyanate was charged in an 80 ° C. reaction kettle sealed with nitrogen gas, and an ultraviolet absorber (2- [2-hydroxy-3,5- Bis (α, α-dimethylbenzyl) phenyl] -2H benzotriazole (TIN234): 20%), antioxidant (3,9-bis (2- (3- (3-t-butyl-4-hydroxy-5) -Methylphenyl) -propionyloxy) -1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane: 50%), light stabilizer (bis (2,2,6) , 6-Tetramethyl-4-piperidyl) sebacate: 30%), and then, while stirring, 69.1 parts of PTMG having a number average molecular weight of 2,000 were injected and stirred for 40 minutes. Stirring was continued to obtain a both-end isocyanate group prepolymer.

Polyurethane elastic fiber melt-spun both-end isocyanate group prepolymer and both-end hydroxyl group prepolymer were continuously fed to a polyurethane elastic fiber reactor at a mass ratio of 1: 0.308. The average residence time in the reactor was about 1 hour, and the reaction temperature was about 197 ° C.

The obtained spinning polymer was introduced into two 8-nozzle spinning heads maintained at a temperature of 197 ° C. without solidifying. The spinning polymer was weighed and pressurized by a gear pump installed on the head, filtered through a filter, discharged from a 1-hole nozzle into a spinning cylinder, wound around a paper tube, and a 33 dtex polyurethane elastic fiber was obtained.
In addition, the ratio of BDO with respect to all the low molecular weight diol (BDO + HDO) was 70 mol%. Further, the nitrogen content (N%) contained in the polyurethane elastic fiber immediately after spinning was 3.2%, and the residual NCO% was 0.35%.

  The obtained wound body was immediately subjected to a solid phase reaction in a room at a temperature of 40 ° C. and a relative humidity of 80% for 5 days.

The heat sealing force of the obtained polyurethane elastic fiber by the SCY knitting method was 0.89 cN / dtex when the wet heat was 115 ° C. and 1.10 cN / dtex when the wet heat was 120 ° C.
Moreover, the heat-resistant strength retention was 63% at 140 ° C. and 57% at 150 ° C.
The heat setting rate was 48% at 140 ° C. and 53% at 150 ° C.
Further, the residual strain at 300% elongation was 24%.

(Knitted fabric by Santony knitting machine)
Production of SCY yarn 2.3 heat-bondable polyurethane elastic fiber (33 dtex, heat-resistant strength retention 63% (140 ° C), heat set rate 48% (140 ° C), residual strain 24%) obtained by melt spinning 2.3 The draft was doubled and coated with 600 T / m (nylon 6, 13 dtex / 5 filament (trade name: Amilan, manufactured by Toray Industries, Inc.)) as a coated yarn to obtain an SCY yarn.

Creation of knitted fabric A brief for men of FIG. 1 and FIG. 2 was prepared by the following procedure using a molding circular knitting machine (manufactured by Santony Co., Ltd., SM8, hook diameter 13 inches).
Here, in FIG. 1, 1 is the base part of the brief, 2 is the penis part, 4 is the waist part, and 5 and 6 are cutting parts. Moreover, in FIG. 2, 3 shows a heel part, 4 shows the site | part corresponding to a waist | hip | lumbar part, and 5 and 7 show the cutting location.

  First, as a knitting yarn, a nylon false twisted yarn 33 decitex 26 filament (product name: Promilan, manufactured by Toray Industries, Inc.) and a single covering yarn are used. The lower part of the brief body was knitted. During this period, the base portion 1 was used, and the braided yarn length was 28.4 cm / 100 W.

  From 101 course, it entered the part 2 corresponding to the penis part of the brief body, and the knitting yarn length of the part was increased by 20% with respect to the base part 1 and knitted to 250 courses. The maximum number of wales in part 2 was 120 wales, and the number of wales was gradually increased toward the top.

  From the 251st course, it entered the part 2 corresponding to the penis part of the brief body and the part 3 corresponding to the buttocks, and the knitting yarn length in the part 3 was also increased by 20% with respect to the base 1, and knitted up to the 600th course. . The number of wales near the apex of the part 3 was also 120 wales, and the number of wales was gradually increased toward the apex of the part 3.

  From the 601st course, it entered the part 3 corresponding to the buttocks of the brief body, and the knitting yarn length in the part 3 was increased by 20% to knit up to the 750th course. The maximum number of wales in part 3 was 120 wales, and the number of wales was gradually increased toward the top of part 3.

  From the 751st course, the knitting yarn length was 28.4 cm / 100 W and knitted up to 800 courses.

  From the 801 course, it corresponds to the waist 4 and is made of a nylon false twisted yarn 33 dtex 24 filaments and two single filament yarns and the single covering yarn, so that a 1 × 1 rubber knitted structure is formed by plating. Organized. At this time, one polyurethane elastic fiber was inserted every 8 courses. The polyurethane elastic fiber includes a heat-fusible polyurethane elastic fiber by melt spinning (33 dtex, heat-bonding force by SCY knitting method 1.10 cN / dtex (120 ° C.), heat-resistant strength retention 63% (140 ° C.), heat A set rate of 48% (140 ° C., residual strain at 300% elongation of 24%) was used. Further, the nylon false twisted yarn was knitted up to 900 courses with a braided yarn length of 30.0 cm / 100 W.

Although the increase / decrease in the above-mentioned knitting yarn length is gradually changed for each course, there is no problem even if the increase / decrease rate is determined for each course.
The knitted fabric width after knitting is 32 cm and the length is 25 cm. It can be heat-set as it is, but it remains on the fibers in the knitted fabric for the purpose of clarifying the shape retention effect of the knitted fabric. In order to release the stress and stabilize the stitch, it was subjected to a release treatment (immersion in a hot water bath) at 100 ° C. for 20 minutes.

Subsequently, the knitted fabric is sufficiently dried, and after measuring the width and length of the knitted fabric, the knitted fabric is mounted on a 35 cm wide formwork so as to have a length of 25 cm. Using a wet heat pantyhose set machine ATR-4P-PN), the wet heat treatment was performed at a wet heat of 120 ° C. for 20 seconds. Thereafter, drying was performed at a dry heat of 110 ° C. for 60 seconds.
Next, based on FIGS. 1 and 2, cutting was performed at the cutting portions 5, 6, and 7, and the cutting portions 6 and 7 were overlapped and sewn.

Thereby, the site | part 2 corresponding to the penis part and the site | part 3 corresponding to the buttocks swelled. Further, the cut portion 5 was cut and the lumbar portion 4 was finished knitting, and a non-sewn three-dimensional molded brief was obtained. The width of the obtained product was 35 cm.
This solid molded brief was worn and evaluated as follows.

Evaluate the degree of thermal fusion Cut the knitted fabric in the course direction and manually check whether the polyurethane elastic fiber at the cut part can be knitted. Was evaluated as poor heat fusion. The results are shown in Table 1.

Dimensional change rate measurement After the knitting, the above-mentioned tubular knitted fabric that was contracted in a hot water bath was used as a sample, the dimensions after predetermined wet heat setting and the dimensions after washing by the following method were measured to obtain the dimensional change rate.
The width and length (cm) of the product after wet heat setting and after washing were measured, and the dimensional change rate (%) was calculated from the following equation (1). The results are shown in Table 2.
Dimensional change rate (%) = (dimension after heat setting-dimension after washing) / dimension after heat setting x 100 (1) Formula

The washing method is as follows.
Laundry was performed under the following conditions using a household 2-tank washing machine (trade name: GINGA4.5 manufactured by TOSHIBA Co., Ltd.).
Laundry (300 minutes) → Centrifugal dehydration (5 minutes) → Rinse water (10 minutes)
→ Centrifugal dehydration (5 minutes)
Liquid temperature: normal temperature (25 ° C), water flow: strong water flow Detergent: manufactured by Kao Corporation, trade name: Attack, water volume: 30 liters 1.3 liters of detergent for 1 liter of washing water Load cloth: cotton and polyurethane elastic fiber For 1.0 kg of mixed bear tengu knitted fabric

Fraying / curl / shape retention evaluation of the knitted fabric by wearing test Repeated wearing, washing and drying of the completed brief for 3 days (all three times), fraying (damage) at the end of the knitted fabric, and during and after wearing The state of curling and the shape retention of the bulging part were observed and evaluated according to the following four levels. The results are shown in Table 3, respectively.

■ Scratch evaluation Regarding the damage evaluation, △ and × indicate that the yarn end protrudes from the cut surface and the cutting line is uneven, and ◎ or ○ indicates that the yarn end does not protrude from the cut surface and the appearance is Good and preferable in terms of washing durability.
<Break evaluation criteria>
A: No damage is observed and there is no difference from before wearing. Good durability.
○: Slightly damaged, but no thread end popping out. Good durability.
Δ: Scratches are recognized and the yarn ends are protruding. Poor durability.
×: Severely bruised and the knitted fabric structure of the cut surface is broken. Poor durability.

■ Evaluation of curl occurrence situation Regarding the evaluation of curl, △ and × indicate that curl has occurred while wearing, and curl does not disappear even after washing. Some parts are visible, or the feeling of wearing is bad, ◎ or ○ does not cause curling while wearing, it does not crack on the outer garment, even if curled after wearing, the curling will be canceled after washing, so clothing As preferred.
<Curl evaluation criteria>
◎: No curling during or after wearing. Good durability.
○: Curling was observed immediately after wearing, but it was resolved by washing and drying. Good durability.
Δ: Curling occurs after wearing and does not disappear even after washing and drying. Poor durability.
X: Curling occurs during wearing, and does not disappear even after washing and drying. Poor durability.

(1) Evaluation of shape retention Further, the shape of the bulging portion was visually observed and evaluated.
△ and X have low shape retention of the bulging part, and it becomes difficult to wear repeatedly, the shape of the bulging part becomes small, and the fitting property of the bulging part which is a feature of a three-dimensional molded knitted fabric is poor ◎ and ○ are preferable as clothing because the change in shape of the bulging portion is small even after repeated wear.
<Evaluation criteria for shape retention of bulge>
A: No change in the shape of the bulge.
○: The shape of the bulging portion was slightly reduced.
(Triangle | delta): The shape of the bulging part became small.
X: The bulging part was in a crushed state.

[Example 2]
A tank top shown in FIG. 3 was prepared by the following procedure using a molding circular knitting machine (manufactured by Santony, MJ-09, pot diameter 17 inches).
Here, in FIG. 3, 8 shows a neck part, 9 shows a shoulder part, 8 shows a side part (cutting location).

  As the knitting yarn, using a yarn in which two nylon false twisted yarn 33 decitex 26 filaments (trade name Promiran manufactured by Toray Industries, Inc.) are aligned and the single covering yarn of Example 1, Knitted up to 1 to 2000 courses to form a tubular knitted fabric. The knitted yarn length was constant at 28.4 cm / 100 W.

  The obtained tubular knitted fabric had a width (in flat placement) of 42 cm and a length of 55 cm. Although it can be heat-set as it is, for the purpose of clarifying the effect of shape retention, it was subjected to a shrinkage treatment in boiling water at 100 ° C. for 20 minutes in order to release the stress remaining on the fibers in the knitted fabric.

  Subsequently, the knitted fabric was sufficiently dried, and the knitted fabric obtained by measuring and extending the width and length of the knitted fabric was attached to a formwork having a width of 46 cm so as to have a length of 55 cm. The set was performed in the same manner.

Subsequently, based on FIG. 3, it cut | judged with the cutting part 8, and the sewing part 9 was piled up and sewed.
As a result, the cut portion 8 was left uncut, and the hem portion 10 was left knitted to obtain a non-sewn tank top. The width of the obtained product was 46 cm.

  The prepared tank top was evaluated in the same manner as in Example 1. The results are shown in Tables 1-3.

[Comparative Example 1]
Polyurethane elastic fiber by dry spinning (Mobilon P type yarn, manufactured by Nisshinbo Co., Ltd., heat fusion force 0.03 cN / dtex (120 ° C.) by SCY knitted fabric method) of polyurethane elastic fiber of Example 1 A knitted fabric similar to that of Example 1 was knitted except that, and the same processing was performed, and then a similar test was performed. The results are shown in Tables 1-3.

[Comparative Example 2]
A knitted fabric similar to that of Example 2 was knitted except that the polyurethane elastic fiber of Example 1 was made of polyurethane elastic fiber by dry spinning (Mobilon P type yarn manufactured by Nisshinbo Co., Ltd.) without heat-fusibility. A similar test was performed after processing. The results are shown in Tables 1-3.

表１中、実施例１，２及び比較例１，２で使用したポリウレタン弾性繊維のＳＣＹ編地法による熱融着力をあわせて示す。

In Table 1, the heat sealing force by the SCY knitted fabric method of the polyurethane elastic fibers used in Examples 1 and 2 and Comparative Examples 1 and 2 is also shown.

The heat-sealed state of Example 1 was good and contained many cut-out portions, so that there was almost no seam to touch the skin, and it was comfortable with a soft wearing feeling. Moreover, the dimensional change by washing was not recognized, and even if it repeated wearing, the flaws, such as fraying of a cut-off part, were not recognized, and there was no difference with before wearing. Further, no curling was observed during and after wearing, the shape of the bulging part was not changed, and the durability of the knitted fabric was good.
In Example 2, the wearing test evaluation was good as in Example 1. In addition, the curl resistance of the cut-out portion was much better. Furthermore, before wearing, drilling holes of any shape such as circles, diamonds, hearts, stars, etc. with a size of about 3cm, and repeating the above-mentioned wearing and washing, there is no run or fraying from the opened holes The product could be used as a product even with a hole.
Since Comparative Example 1 was inferior in heat-fusibility, fraying occurred from the cut portion by repeated wearing. The edge of the knitted fabric was curled and uncomfortable when worn. Shrinkage was caused by washing, and the bulge was crushed. Since the shrinkage due to washing was large, the wearing feeling was tight compared to Example 1, and inferior in all.
Since Comparative Example 2 was inferior in heat-fusibility like Comparative Example 1, fraying occurred from the cut portion by repeated wearing. Since the curl tends to be stopped by the knitting structure, it returned to its original state by washing and drying. However, the shrinkage due to washing was large as in Comparative Example 1, and the feeling of wearing became tighter than in Example 2.

In the present invention, an efficient and effective shape retention function and a run / fray prevention function can be imparted to the molded knitted fabric by using the wet heat setting process as a conventional process as it is.
Moreover, even if a hole is partially generated, it will not fray, so that the damage will not spread further. Since fraying or the like does not spread from the cut portion, the molded knitted fabric of the present invention can be used after being cut or melted into an arbitrary shape.

It is a pattern figure which shows an example (Brief front body for gentlemen) of this invention. It is a pattern figure which shows an example (the gentleman's brief back body) of this invention. It is a pattern diagram which shows another example (tank top) of this invention.

Claims (12)

  A molded knitted fabric having a shape-retaining function and a run / fray-preventing function, wherein a knitted fabric (excluding an undercarriage knitted fabric) containing heat-fusible elastic fibers is subjected to a wet heat treatment.   The molded knitted fabric according to claim 1, wherein the molded knitted fabric is formed by a plating knitting using a front yarn made of non-elastic fibers and a back yarn made of heat-fusible elastic fibers.   The molded knitted fabric according to claim 1, wherein the composite knitted fabric is formed by a plating knitting using a front yarn made of non-elastic fibers and a back yarn made of composite yarn, and the composite yarn contains heat-fusible elastic fibers.   The molded knitted fabric according to claim 3, wherein the composite yarn comprises a core yarn made of heat-fusible elastic fibers and non-elastic fibers covering the core yarns.   The molded knitted fabric according to claim 4, wherein the composite yarn is a covering yarn, a twisted yarn or an air entangled yarn.   The molded knitted fabric according to claim 5, wherein the covering yarn is a single covering yarn.   The heat-sealable elastic fiber is a heat-sealable polyurethane elastic fiber having a heat-seal strength of 0.15 cN / dtex or more when wet-heat treated at 120 ° C for 20 seconds in a single covering yarn knitted fabric method. The molded knitted fabric according to any one of the above.   The molded knitted fabric according to claim 7, wherein the heat-fusible polyurethane elastic fiber has a heat-sealing force of 0.30 cN / dtex or more.   The heat-sealable elastic fiber is a heat-sealable polyurethane elastic fiber having a heat-seal strength of 0.15 cN / dtex or more when wet-heat treated at 115 ° C for 20 seconds in a single covering yarn knitted fabric method. The molded knitted fabric according to any one of the above.   The molded knitted fabric according to claim 9, wherein the heat-fusible polyurethane elastic fiber has a heat-sealing force of 0.30 cN / dtex or more.   The molded knitted fabric according to any one of claims 7 to 10, wherein the heat-sealable polyurethane elastic fiber has a heat-resistant strength retention rate of 40% or more when subjected to a dry heat treatment at 140 ° C for 45 seconds under double elongation. . The molded knitted fabric according to any one of claims 1 to 11, wherein an arbitrary hole is formed or cut into an arbitrary shape.

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