JP5105039B2 - Heat-sealable polyurethane elastic fiber, method for producing the same, and woven / knitted fabric using the polyurethane elastic fiber - Google Patents

Description

  The present invention relates to a heat-fusible polyurethane elastic fiber which is excellent in heat-fusibility during wet heat treatment and hardly breaks or deteriorates, a method for producing the same, and a woven or knitted fabric using the heat-fusible polyurethane elastic fiber.

  Polyurethane elastic fibers are widely used because of their large elongation and good recovery from the stretched state and good fit.

  However, when a product made by cutting and sewing a polyurethane elastic fiber is repeatedly stretched, it becomes deformed and becomes a non-uniform fabric. “Deformation, misalignment, soft”, “Fray”, the yarn comes out. Problems such as “run, densen” with ladder-like scratches and misalignment, and “curl” with curved fabric are likely to occur. In addition, the so-called “slip-in”, in which the polyurethane elastic fiber comes out of the seam at the sewing portion due to repeated elongation, tends to occur. Naturally, the portion of the fabric from which the slip-in occurs and the elastic fibers are pulled out has a problem that density shrinkage occurs on the fabric because the shrinkage force is lost, and the fabric cannot be worn.

  These phenomena occur even in a woven or knitted fabric using elastic fibers other than polyurethane elastic fibers, but are particularly remarkable in the case of polyurethane elastic fibers having strong stretchability.

  In order to cope with these problems, Japanese Patent Application Laid-Open No. 2002-339189 (Patent Document 1) discloses a method of improving the heat-fusibility of fibers by dry spinning a polyurethane urea polymer solution to which a urea compound is added. Has been proposed.

  In addition, a polyurethane elastic fiber obtained by melt spinning and having improved heat-sealability having a certain tenacity retention and melting point has also been proposed (Patent Document 2: WO2004 / 053218).

  However, in the said patent document 1, it heat-fused by dry-heat-treating at 160-195 degreeC, and the heat-fusible polyurethane elastic fiber heat-sealed by wet-heat treatment was not proposed. On the other hand, for Patent Document 2, further improvement in heat-fusibility during wet heat treatment has been demanded.

JP 2002-339189 A WO2004 / 053218

  The present invention has been made in view of the above circumstances, and provides a polyurethane elastic fiber that exhibits heat-fusibility useful in the clothing field by wet heat treatment, a method for producing the same, and a woven or knitted fabric obtained using the polyurethane elastic fiber. The purpose is to do.

  The present inventors have studied to achieve the above object and have proposed a heat-sealable polyurethane elastic fiber with improved yarn breaking characteristics (Japanese Patent Laid-Open No. 2006-307409). As a result of earnest studies for further improvement of the fusing property, the polyurethane elastic fibers can be sufficiently heat-sealed even in the wet heat treatment, which has a lower heat load than the dry heat treatment, and the polyurethane elastic fiber and its common fiber It has been found that it is important for the solution of the above-mentioned problems to increase the fusion effect. As a result of research based on this finding, in the single covering yarn (SCY) knitted fabric method, the heat fusion force when wet-heat treated at 120 ° C. for 20 seconds, particularly at 115 ° C. for 20 seconds is 0.30 cN / The heat-sealable polyurethane elastic fiber of dtex or more is produced through a wet heat treatment process, especially in the garment field where stretchability is required, and it is excellent in preventing wire lines and fraying without impairing the texture of the knitted fabric In addition, the present inventors have found that a heat-fusible polyurethane elastic fiber having the above characteristics can be obtained under a predetermined condition, and has made the present invention.

That is, the present invention
[1] A heat-fusible polyurethane elastic fiber having a heat-fusibility of 0.30 cN / dtex or more when wet-heat treated at 120 ° C. for 20 seconds in a method for measuring heat-fusibility by a single covering yarn knitted fabric method. ,
The heat-fusible polyurethane elastic fiber is obtained by reacting a polyol, diisocyanate and at least two kinds of low molecular weight diols having 2 to 6 carbon atoms, and the content of the low molecular weight diol which is the main of the low molecular weight diols is The heat is characterized in that it is 55 mol% or more and less than 80 mol% with respect to the total low molecular weight diol, and the nitrogen content of the polyurethane elastic fiber immediately after spinning is 2.8 mass% or more and 3.4 mass% or less. Fusible polyurethane elastic fiber,
[2] A heat-sealable polyurethane elastic fiber having a heat-seal strength of 0.30 cN / dtex or more when wet-heat treated at 120 ° C. for 20 seconds in a method for measuring heat-seal strength by a single covering yarn knitted fabric method, ,
The heat-fusible polyurethane elastic fiber is obtained by reacting a polyol, diisocyanate and at least two kinds of low molecular weight diols having 2 to 6 carbon atoms, and the content of the low molecular weight diol which is the main of the low molecular weight diols is The heat is characterized in that it is 80 mol% or more and less than 98 mol% with respect to the total low molecular weight diol, and the nitrogen content of the polyurethane elastic fiber immediately after spinning is 2.2 mass% or more and 3.4 mass% or less. Fusible polyurethane elastic fiber,
[3] The heat described in [1] or [2], wherein in the method for measuring the thermal fusing force by the single covering yarn knitted fabric method, the thermal fusing force when wet-heat treated at 115 ° C. for 20 seconds is 0.30 cN / dtex or more. Fusible polyurethane elastic fiber,
[4] The heat-sealable polyurethane elastic fiber according to any one of [1] to [3], wherein a residual strain immediately after 300% elongation is 40% or less,
[5] (I) A reaction between a first polyol and a diisocyanate, both terminal isocyanate group prepolymers, and (II) a second polyol, a diisocyanate, and at least two low molecular weight diols having 2 to 6 carbon atoms. The heat-fusible polyurethane elastic fiber according to any one of [1] to [4], which is obtained by melt spinning a polymer obtained by reacting the both-terminal hydroxyl group prepolymer obtained in the above,
[6] The at least two low molecular weight diols having 2 to 6 carbon atoms are diols 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. The main low molecular weight diol is a diol having 2 and / or 4 carbon atoms, or at least two low molecular weight diols having 2 to 6 carbon atoms are diols having 6 carbon atoms and 3 and / or carbon atoms The heat-fusible polyurethane elastic fiber according to any one of [1] to [5], wherein the main low molecular weight diol is a diol having 6 carbon atoms,
[7] The heat according to [5] or [6], wherein the first and second polyols are polyether diol and / or polyester diol, and the ratio of the polyester diol to the total polyol is 55 mol% or more and 95 mol% or less. Fusible polyurethane elastic fiber,
[8] The first and second polyols are polyether diols and / or polyester diols, and the ratio of the polyether diol to the total polyols is 60 mol% or more and 100 mol% or less. [5] or [6] Heat-sealable polyurethane elastic fiber,
[ 9 ] The molar ratio of all diisocyanates to the total amount of all polyols and all low molecular weight diols is 0.95 to 1.25, and the molar ratio of all diisocyanates to all polyols is 2.4 to 3.8. The heat-fusible polyurethane elastic fiber according to any one of [1] to [ 8 ], wherein the residual isocyanate group in the yarn immediately after spinning is 0.2 to 1.0% by mass,
[ 10 ] A single covering yarn, a core spun yarn, a twisted yarn or an air entangled yarn, wherein the core yarn comprising the heat-fusible polyurethane elastic fiber according to any one of [1] to [ 9 ] is coated with an inelastic yarn. Composite yarn, which is
[ 11 ] A heat-fusible polyurethane elastic fiber according to any one of [1] to [ 9 ], or a polyurethane elastic fiber mixed woven or knitted fabric obtained by weaving and knitting a mixture of this and other fibers.
[ 12 ] The heat-fusible polyurethane elastic fiber according to any one of [1] to [ 9 ] and at least one type of inelastic yarn, and / or heat-fusible polyurethane elastic fiber and / or each other by wet heat treatment. [ 11 ] The polyurethane elastic fiber mixed woven or knitted fabric according to [ 11 ], wherein the intersection between the elastic yarn and the inelastic yarn is heat-sealed.
[ 13 ] A woven fabric having a warp and / or weft of a composite yarn including the heat-fusible polyurethane elastic fiber according to any one of [1] to [ 9 ] and at least one kind of inelastic yarn [ 12] ] Woven or knitted fabric mixed with polyurethane elastic fiber,
[ 14 ] Using the heat-fusible polyurethane elastic fiber according to any one of [1] to [ 9 ] and at least one inelastic yarn for the same course of a knitting machine, the heat-fusible polyurethane elastic fiber Polyurethane elastic fiber mixed woven or knitted fabric according to [ 12 ], wherein the knitted fabric is a weft knitted fabric used as a composite yarn with insertion, knitting or plating knitting or the inelastic yarn,
[ 15 ] The heat-fusible polyurethane elastic fiber according to any one of [1] to [ 9 ] and at least one non-elastic yarn, and the heat-fusible polyurethane elastic fiber is inserted or knitted. The polyurethane elastic fiber mixed woven or knitted fabric according to [ 12 ], which is a knitted fabric,
[ 16 ] Briefs, panties, shorts, undershirt, camisole, girdle, bra, spats, body suit, sanitary shorts, underwear, swimsuit, leotard, resort wear, home wear, underwear, shirt, outerwear, gloves, Arm cover, medical clothing, surgical clothing, cleanroom work clothing, dustproof clothing, supporters, eye masks, clothing products, disposable diapers, incontinence pads, gauze, bandages, patch materials, packaging materials, masks, sheets, towels, handkerchiefs [ 11 ] to [ 15 ], a polyurethane elastic fiber mixed woven or knitted fabric according to any one of [ 11 ] to [ 15 ], which is a sanitary article, a clothing interlining, a microfiltration filter, an industrial wiper, a protective cover, or an industrial material;
[ 17 ] (I) a step of reacting the first polyol and the diisocyanate to synthesize both terminal isocyanate group prepolymers,
(II) a step of synthesizing both terminal hydroxyl group prepolymers by reacting the second polyol, diisocyanate and at least two low molecular weight diols having 2 to 6 carbon atoms;
(III) a step of synthesizing a spinning polymer by reacting both terminal isocyanate group prepolymers and both terminal hydroxyl group prepolymers;
(IV) including a step of melt-spinning a spinning polymer, wherein the content of the main low molecular weight diol among the low molecular weight diols is 55 mol% or more and less than 80 mol% with respect to the total low molecular weight diol, A method for producing a heat-fusible polyurethane elastic fiber, wherein the nitrogen content of the polymer immediately after is 2.8% by mass to 3.4% by mass,
[ 18 ] (I) A step of reacting the first polyol and diisocyanate to synthesize both terminal isocyanate group prepolymers,
(II) a step of synthesizing both terminal hydroxyl group prepolymers by reacting the second polyol, diisocyanate and at least two low molecular weight diols having 2 to 6 carbon atoms;
(III) a step of synthesizing a spinning polymer by reacting both terminal isocyanate group prepolymers and both terminal hydroxyl group prepolymers;
(IV) including a step of melt-spinning a spinning polymer, and the content of the main low molecular weight diol among the low molecular weight diols is 80 mol% or more and less than 98 mol% with respect to the total low molecular weight diol, and spinning producing how heat-fusible polyurethane elastic fiber characterized in that nitrogen content immediately after the polymer is 3.4 wt% or less than 2.2 wt%
To provide.

According to the present invention, it is possible to provide a heat-sealable polyurethane elastic fiber that is less prone to fraying, misalignment, softness, densen, run, curl, slip-in and the like (hereinafter referred to as fraying). Moreover, the polyurethane elastic fiber of the present invention can be used as a composite yarn such as SCY having a core yarn and the periphery thereof covered with a non-elastic yarn, and a woven or knitted fabric that is less likely to fray by wet heat treatment can be obtained.
Fraying is less likely to occur because the polyurethane elastic fibers are melted by wet heat treatment, and the polyurethane elastic fibers and / or the intersections between the elastic elastic fibers and the non-elastic yarn, or the polyurethane elastic fibers and the polyurethane elastic fibers are coated. The heat fusion force is 0.3 cN / dtex or more when heat fusion is performed at the intersection with the composite yarn made of inelastic yarn, and further at the intersection between the composite yarns, and when wet heat treatment is performed under predetermined conditions in the SCY knitting method. By becoming.

  The polyurethane elastic fiber of the present invention has a heat-fusibility with a heat-fusibility of 0.30 cN / dtex or more when wet-heat treated at 120 ° C. for 20 seconds, particularly at 115 ° C. for 20 seconds in the single covering yarn knitted fabric method. Polyurethane elastic fiber.

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 2,400 courses, 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 (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 degree of thermal fusion between the polyurethane elastic fibers or between the polyurethane elastic fibers and the nylon used is increased, the knitting tension of the SCY is increased. When the thermal fusion is further advanced and the thermal fusion is further strongly carried out, the polyurethane elastic yarn in the gripped SCY is broken by elongation, and only the nylon remaining in the gripping portion is pulled out. In this case, “complete fusion” It represents that the thermal fusion power has reached the maximum.

  The reason for using the SCY knitted fabric method in this evaluation is that the polyurethane elastic fiber used for the knitted fabric for performing the wet heat treatment of the present application may be a bare yarn, but it may be a covering yarn, a twisted yarn, an air entangled yarn. Compared to the case where the polyurethane elastic fiber and the common fiber are used in the plating knitting, the number of contact points between the polyurethane elastic fibers is reduced and the fusion elastic fiber is used as a composite yarn. This is to evaluate the effect under disadvantageous conditions and more severe conditions.

  In addition, in the heat treatment, in order to reduce the energy loss, the knitted fabric does not become hard, and the soft texture of the used fiber itself is maintained, the temperature is 125 ° C. from 130 ° C., 120 ° C. from 125 ° C. Processing at a low temperature has been demanded, and it has been a long-standing problem to exert a great fusion effect at 120 ° C. or lower using an SCY knitted fabric.

  The polyurethane elastic fiber of the present invention has a heat fusion strength of 0.30 cN / dtex or more in the single covered yarn knitted fabric method. If the heat sealing force is less than 0.30 cN / dtex, a run occurs when the knitted fabric or the product is repeatedly used, or a run or a fray occurs when the knitted fabric is repeatedly used after being cut off. . For example, in the case of a disposable product that is disposed of only once, if it has a heat-sealing power of 0.1 cN / dtex or more, it has durability against run or fraying. In addition, 0.30 cN / dtex or more is required in order to use a product that is used repeatedly without worrying about problems such as run or fraying.

  In addition, as the thermal fusing force increases, the durability against run and fraying increases, and it is desirable that the thermal fusing force is preferably 0.4 cN / dtex or more, more preferably 0.8 cN / dtex or more. If the wet heat treatment is strengthened to increase the adhesion, the shared fiber may become harder and the texture may be lowered, and it is desirable to appropriately select conditions under which an appropriate heat fusion force and the original texture of the used fiber are expressed.

  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 is considered that a thermal fusing force of 0.30 cN / dtex or more can be obtained by the SCY knitted fabric method by fusing the common fiber used together with the fiber.

  Here, in the present invention, heat fusion refers to a state in which polyurethane elastic fibers are bonded to each other and / or polyurethane elastic fibers and / or other fibers by wet heat treatment, It means a state in which at least a part is fused and in close contact, or a state in which fibers are bonded even if the fusion does not occur.

  The heat-fusible polyurethane elastic fiber of the present invention preferably further has the following physical properties.

  That is, the polyurethane elastic fiber of 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 elongation when the stress becomes zero when the grip length is 4 cm, and after stretching to 16 cm at 300 mm / min, immediately after restoring to the original length at the same speed as when stretching. Based on the following formula:
Residual strain = (residual elongation cm / 4 cm) x 100 (%)

  Further, the value of the heat-resistant strength retention rate when subjected to a dry heat treatment at 150 ° C. for 45 seconds under double elongation is preferably 20% or more, and particularly preferably 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.

  Furthermore, when the polyurethane elastic fiber of 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 treated at 150 ° C. for 45 seconds. It is preferable that the strength retention ratio is 20% or more and the strength retention ratio when treated 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 heat-processes by putting for 45 second in the hot air dryer maintained at predetermined temperature in the expand | extended state. 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.

  Further, when the polyurethane elastic fiber of 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. Moreover, it is preferable that the heat set rate when processed at 150 degreeC for 45 second becomes 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. 30 seconds after the end of the heat treatment, the grip length is 4 cm and the yarn is loosened. After 5 minutes and 30 seconds from the end of the heat treatment, the grasping length is increased and the grasping length is narrowed by 1 mm after being slightly extended. 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

  The method for producing the polyurethane elastic fiber of the present invention is not particularly limited as long as the polyurethane elastic fiber having the above characteristics can be obtained, and either a melt spinning method or a dry spinning method 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 glycol, polyester glycol, and polycarbonate glycol exemplified above can be used alone or in combination of two or more, but it is preferable to use polyether diol and / or 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, and 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.

  Moreover, as a low molecular weight diamine, ethylenediamine, butanediamine, propylenediamine, hexamethylenediamine, xylylenediamine, 4,4-diaminodiphenylmethane, hydrazine, etc. can be used, for example.

  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 55 mol% or more and 95 mol% or less, 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 all polyols is 60 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol%. % Or less is preferable. 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. A polyether polyol component is preferably selected as the first polyol because alkali resistance is increased.

  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 fiber elongation recovery rate, compression set, and heat resistance when the combined amount is less than 55 mol%. May get worse.

  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 2.9 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 thermal fusion force becomes low.

  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 In view of the above, it is preferable that the diol having 6 carbon atoms is mainly used.

  Further, (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%. % Or more and 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, a polyurethane elastic fiber excellent in heat-fusibility is obtained by a method combining the condition (1a) or (1b) with the condition (2a), (2b) or (2c). Can be obtained, and under the respective conditions, a unique effect can be brought about as described above.

  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.

  The fineness of the heat-sealable polyurethane elastic fiber of the present invention can be appropriately selected from both the shape retention performance and production cost of the elastic fiber structure, and is preferably 11 to 800 dtex from the viewpoint of ease of production and cost. More preferably, it is 17-622 dtex. Most preferably, it is 17-156 dtex. In the obtained heat-fusible polyurethane elastic fiber, it is advantageous for improving the heat setting property that the dtex per single yarn is large.

The fineness is measured by releasing the yarn from the wound body, allowing it to stand for 24 hours and then shrinking it, and then placing the yarn along a straight line drawn on the fineness measurement plate in a state of no tension, to a length of 100 cm. The main cut is made and the mass for a total of 50 is measured.
Fineness (dtex) = measured mass (mg) / 50 × 10

  The heat-fusible polyurethane elastic fiber outside the fineness range of the SCY knitting method has the same heat-melting force as that of the heat-fusible polyurethane elastic fiber (of the same composition) with a fineness of 11 to 156 dtex. By measuring the force.

  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-mentioned production method has a heat fusion force of 0.30 cN / dtex or more when wet-heat treated at 120 ° C. for 20 seconds, particularly at 115 ° C. for 20 seconds in the SCY knitting method. By using the knitted fabric, it is possible to obtain a woven or knitted fabric in which the occurrence of fraying and the like is suppressed.

  Further, the heat-sealable polyurethane elastic fiber of the present invention is a composite yarn containing a heat-sealable polyurethane elastic fiber, specifically, the heat-sealable polyurethane elastic fiber as a core yarn and a non-elasticity as a coated fiber. It can be used for woven and knitted fabrics as SCY, core spun yarn, or twisted yarn using yarn, and good heat-sealing force can be obtained by wet heat treatment.

  Next, the polyurethane elastic fiber-mixed woven or knitted fabric of the present invention includes the above heat-fusible polyurethane elastic fiber (raw yarn) or a composite yarn such as SCY using the heat-fusible polyurethane elastic fiber as a core yarn, and an inelastic yarn. The following structure can be used.

  The heat-sealable polyurethane elastic fiber may be any of raw yarn (unprocessed yarn), false twisted yarn, pre-dyed yarn, or a composite yarn thereof. Furthermore, a high melting point polyurethane elastic fiber may be mixed.

  (1) A fabric using a composite yarn containing a heat-fusible polyurethane elastic fiber and at least one inelastic yarn as a warp and / or a weft. The texture may be any of plain weave, twill weave, satin weaving, and the like, and shuttle looms, rapier looms, air jet looms and the like can be used as the loom. Furthermore, the warp and the weft may be the composite yarn, or the composite yarn and the inelastic yarn may be mixed and used at a driving ratio of 1: 1, 1: 2, or 1: 3.

  (2) A weft knitted fabric in which a heat-fusible polyurethane elastic fiber and at least one kind of inelastic yarn are mixed in the same course of a knitting machine. The knitting structure of the weft knitted fabric knitted with the heat-fusible polyurethane elastic fiber and the non-elastic yarn may be any structure such as a flat knitting, a rubber knitting, a pearl knitting, a double-sided knitting, and a structure obtained by combining or changing these. All knitting machines such as circular knitting machines, flat knitting machines, full fashion knitting machines, sweater knitting machines, sock knitting machines, garment-length knitting machines, etc. are used as knitting machines. be able to. The heat-sealable polyurethane elastic fiber may be either inserted or knitted. Also, a plating knitting of heat-fusible polyurethane elastic fiber and inelastic yarn may be used, or a composite yarn of heat-fusible polyurethane and inelastic yarn may be used. Similarly to (1), the heat-sealable polyurethane elastic fiber may be knitted in all courses, or may be knitted every other course. The heat-sealable polyurethane elastic fiber and inelastic yarn may be knitted alternately or at appropriate intervals. Further, heat-sealable polyurethane elastic fibers may be mixed.

  (3) A warp knitted fabric in which heat-fusible polyurethane elastic fibers and at least one kind of inelastic yarn are mixed. The knitting structure of the warp knitted fabric knitted with heat-fusible polyurethane elastic fiber and inelastic yarn is any structure such as combed knitting, denvi knitting, cord knitting, atlas knitting, or a combination or change of these. All the knitting machines such as a tricot knitting machine, a Raschel knitting machine, and a Milanese knitting machine can be used. As in (1), heat-sealable polyurethane elastic fibers may be knitted on the entire surface, or may be knitted at appropriate intervals. The heat-sealable polyurethane elastic fiber may be either inserted or knitted.

  The non-elastic yarn mixed with the heat-sealable polyurethane elastic fiber is not particularly limited. For example, natural fibers such as cotton, hemp, wool and silk, regenerated fibers such as rayon, cupra and polynosic, and semi-regenerated fibers such as acetate. Fibers such as fibers, nylon, polyester, acrylic, polypropylene, vinyl chloride and other chemically synthetic fibers can be used, but the mixed proportion of polyurethane elastic fibers is about 1 to 60% by mass, especially about 2 to 50% by mass. Is preferred.

  The method for producing a highly fusible polyurethane elastic fiber mixed woven or knitted fabric of the present invention can be obtained by weaving or knitting a woven fabric or knitted fabric having the above-described structure by a conventional method, and then performing wet heat treatment (setting).

The wet heat setting method uses, for example, a steam setter manufactured by Iwata Manufacturing Co., Ltd., opens the steam valve at a steam source pressure of 2.5 to 3.0 kg / cm ² , and puts steam into a sealed set chamber, The set room is controlled to a predetermined temperature. In this case, the set temperature is 80 to 140 ° C, particularly 90 to 135 ° C. Next, the woven / 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.

  If the heat setting temperature is too low, the setting effect is insufficient or the dimensional stability and shrinkage characteristics of the knitted fabric are inferior, which is undesirable. If it is too high, the strength of the inelastic yarn is reduced, thermal discoloration, the texture becomes hard, etc. This is not preferable because of the negative effects.

  Woven knitted fabrics using such heat-fusible polyurethane elastic fibers include briefs, panties, shorts, undershirts, camisole, girdle, bra, spats, body suits, sanitary shorts and other underwear, swimwear, leotards, Resort wear, home wear, underwear, sports tights, shirts, outerwear, gloves, socks, arm covers, medical clothing, surgical clothing, clothing for cleanroom work in semiconductor factories, dustproof clothing, supporters, eye masks, etc. Apparel products, disposable diapers, incontinence pads, gauze, bandages, patch materials, packaging materials, masks, sheets, towels, handkerchiefs and other hygiene products, clothing interlinings, microfiltration filters, industrial wipers, protective covers, etc. Used in fields that require high stretchability and stretch recovery, such as industrial materials.

  In particular, the polyurethane elastic fiber of the present invention can be suitably used for apparel that is wet-heat treated, such as underwear knitted fabric products such as stockings, and molded knitted fabrics that are knitted into products.

EXAMPLES Hereinafter, although an Example , a reference example, and a comparative example are shown and this invention is demonstrated more concretely, this invention is not restrict | limited to the following Example. In addition, in the following example, a part shows a mass part. The residual NCO% is a value measured by a titration method using hydrochloric acid. The number average molecular weight was measured according to JIS K1557.

[Example 1] Production of polyurethane elastic fiber by melt spinning method (with low molecular weight diol second component (i))
Synthetic diisocyanate of both terminal hydroxyl group prepolymers 23.5 parts of 4,4'-diphenylmethane diisocyanate (MDI) was charged into a reaction kettle with a warm water jacket at 80 ° C. sealed with nitrogen gas, where the number average molecular weight was 1 as a polymer diol. 41,000 parts of 4,000 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 further 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 a reaction vessel with a warm water jacket at 80 ° C. sealed with nitrogen gas, and an ultraviolet absorber (2- [2-hydroxy- 3,5-bis (α, α-dimethylbenzyl) phenyl] -2Hbenzotriazole (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 a polyethylene adipene having a number average molecular weight of 2,100 with stirring. 69.1 parts of a salt (PEA) was injected, and stirring was continued for 40 minutes to obtain a both-end isocyanate group prepolymer.

Both ends isocyanate group prepolymer and both ends hydroxyl group prepolymer obtained by melt spinning of polyurethane elastic fiber were continuously fed to a cylindrical reactor for polyurethane elastic fiber 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 isocyanate group (residual NCO%) was 0.43%.

  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 polyurethane elastic fiber (surface layer) was doubled and placed in a hot air dryer maintained at 140 ° C. for 45 seconds for heat treatment. The heat resistant strength retention rate for the fibers before the heat treatment was 57%. Further, the polyurethane elastic fiber (surface layer) was doubled and placed in a hot air drier maintained at 150 ° C. for 45 seconds for heat treatment. The heat resistant strength retention rate for the fibers before the heat treatment was 40%.
The residual strain immediately after extending the polyurethane elastic fiber (surface layer) by 300% was 30%. The heat setting rate was 50% at 140 ° C. and 59% at 150 ° C.
Here, the surface layer refers to the outermost surface layer of the wound yarn body and a region corresponding to 10% by mass of the entire winding amount.

Production of Single Covering Yarn (SCY) Polyurethane elastic fiber (33 dtex) obtained was used as a core yarn, nylon filament yarn 13 dtex 5 filament was used as a covering yarn, and covered at a draft magnification of 2.3 times and a twist number of 600 T / M.

Pantyhose production SCY Pantyhose knitting fabric production Pantyhose knitting machine (Lunaty L416 / R, hook diameter: 4 inches, 400 needles) SCY is fed into the yarn feeder, 2400 counts, 45cm stretch And the pantyhose knitted fabric was produced only with SCY.
Using a steam setter manufactured by Heat Set Co., Ltd. and placed in an aluminum template with a width of 11 cm, the fabric stretches 1.2 times in the well direction, and the knitted fabric is wet heat 115 while maintaining this state. Each was set at 20 ° C. and 120 ° C. for 20 seconds.

Run evaluation SCY A knitted fabric was cut with scissors at any five points on one side of the knitted fabric, and a curved acrylic plate (an acrylic plate attached to a sock / stocking size measuring instrument Mizura Torre manufactured by Cetome Co., Ltd.) was used. The approximate dimensions of the acrylic plate are about 20 cm in width, about 80 cm in length, and the depth of the recess is about 4 cm at the maximum).
At this time, it is inserted so that the cut surface of the stitch is on the concave side of the plate. Since the knitted surface is inserted without being in contact with the plate surface, the run (wire transmission) is most likely to occur. The run resistance of the pantyhose was evaluated based on the presence or absence of the run.
In addition, when inserting a knitted fabric into this acrylic board, it is preferable to apply the force equivalent to or more than the force applied to the pantyhose at the time of wearing. For example, it may be inserted quickly by hand, or may be inserted by applying a constant load (1 kgf) to the knitted fabric. In Examples and Comparative Examples, the evaluation was performed by quickly inserting the knitted fabric by hand. Insertion into the curved acrylic plate was repeated a total of two times, and then the occurrence of the run was observed.
○: Run does not occur ×: Run occurs

Stocking knitted fabric evaluation The stocking knitted fabric is made of acrylic and passed through a black flat plate (width 10 cm, length 88 cm), and the state of the spots is visually evaluated.
○: Level of knitted fabric is high and good level △: Level of knitted fabric is slightly inferior, but it can be used ×: Level of knitted fabric is low and cannot be used

The heat sealing force in the SCY knitted fabric method was 0.65 cN / dtex when the wet heat was 115 ° C. and 1.12 cN / dtex when the wet heat was 120 ° C. In the run evaluation, no run was generated, and it was confirmed that the heat fusion property was excellent.
The knitted fabric unevenness evaluation of the pantyhose showed a high degree of uniformity of the knitted fabric and no unevenness.

  Moreover, since the set rate in wet heat was good, it was finished greatly, so it was easy to wear. In addition, even when washing was repeated 10 times, the stitches were excellent in stability, so that a beautiful knitted surface with uniform stitches was maintained.

[Example 2] Production of polyurethane elastic fiber by melt spinning method (with low molecular diol second component (ii))
Synthetic diisocyanate of both terminal hydroxyl group prepolymers , 43.9'-diphenylmethane diisocyanate (MDI) was charged into a reaction kettle with a hot water jacket at 80 ° C sealed with nitrogen gas, and the number average molecular weight was used as a polymer diol. 49.0 parts of 1,000 polytetramethylene ether glycol (PTMG) was injected with stirring and allowed to react for 1 hour. Subsequently, 22.5 parts of 1,4-butanediol (BDO) was injected as a low molecular weight diol and allowed to react for 1 hour. Further, 4.6 parts of 1,5-pentanediol (PEDO) 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.

Synthesis of both-end isocyanate group prepolymers Both-end isocyanate group prepolymers were synthesized in the same manner as in Example 1.

Polyolefin elastic fiber melt spinning The obtained both-end isocyanate group prepolymer and both-end hydroxyl group prepolymer were continuously fed to a reactor for polyurethane elastic fiber at a mass ratio of 1: 0.308, as in Example 1. In this manner, 33 dtex polyurethane elastic fiber was produced.
In addition, the ratio of BDO with respect to all the low molecular weight diols (BDO + PEDO) was 85 mol%. The nitrogen content (N%) contained in the polyurethane elastic fiber immediately after spinning was 3.2%, and the residual NCO% was 0.43%.

When the physical properties of the finished yarn were measured in the same manner as in Example 1, the tenacity retention after heat treatment at 140 ° C. was 52%. The strength retention after heat treatment at 150 ° C. was 29%.
The residual strain immediately after extending the polyurethane elastic fiber (surface layer) by 300% was 33%. The heat setting rate was 58% at 140 ° C. and 65% at 150 ° C.

SCY and a pantyhose knitted fabric were produced in the same manner as in Example 1, and wet heat set.
The heat sealing force in the SCY knitting method was 0.59 cN / dtex when the wet heat was 115 ° C. and 1.03 cN / dtex when the wet heat was 120 ° C. In the run evaluation, no run was generated, and it was confirmed that the heat fusion property was excellent.

  The knitted fabric unevenness evaluation of the pantyhose showed a high degree of uniformity of the knitted fabric and no unevenness. Moreover, since the set rate in wet heat was good, it finished greatly. In addition, since the stitches were excellent in stability even after washing was repeated 10 times, a beautiful knitted surface with uniform stitches was maintained.

[ Reference Example 1 ] Production of polyurethane elastic fiber by melt spinning method (low N%)
Synthetic diisocyanate of both terminal hydroxyl group prepolymers 4,4'-diphenylmethane diisocyanate (MDI) was charged in a reaction kettle with a warm water jacket at 80 ° C. sealed with nitrogen gas, and the number average molecular weight was used as a polymer diol. 49.3 parts of 1,000 polytetramethylene ether glycol (PTMG) were injected with stirring. After the reaction for 1 hour, 26.6 parts of 1,4-butanediol (BDO) was further injected as a low molecular weight diol, 1.0 part of bis (4-hydroxyphenyl) sulfone (BHPS) was added, and the mixture was stirred for 15 minutes. Thus, a hydroxyl group prepolymer at both ends was synthesized.

In parallel with this, 23.8 parts of MDI as diisocyanate was charged in a reaction vessel with a hot water jacket at 80 ° C. sealed with nitrogen gas, and a UV absorber (2- [2-hydroxy- 3,5-bis (α, α-dimethylbenzyl) phenyl] -2Hbenzotriazole (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 a polyethylene adip having a number average molecular weight of 2,100 with stirring. 74.9 parts of PEA (PEA) was injected and stirring was continued for 40 minutes to obtain a both-end isocyanate group prepolymer.

Polyurethane elastic fiber melt-spun both-end isocyanate group prepolymer and both-end hydroxyl group prepolymer are continuously fed to the polyurethane elastic fiber reactor at a mass ratio of 1: 0.205, and the same method as in Example 1 is used. A 33 dtex polyurethane elastic fiber was produced. The nitrogen content (N%) contained in the polyurethane elastic fiber immediately after spinning was 2.7%, and the residual NCO% was 0.43%.

When the physical properties of the finished yarn were measured in the same manner as in Example 1, the tenacity retention after heat treatment at 140 ° C. was 45%. The strength retention after heat treatment at 150 ° C. was 20%.
Further, the residual strain immediately after stretching the polyurethane elastic fiber (surface layer) by 300% was 35%. The heat setting rate was 60% at 140 ° C and 67% at 150 ° C.

SCY and a pantyhose knitted fabric were produced in the same manner as in Example 1, and wet heat set.
The heat sealing force in the SCY knitted fabric method was 0.45 cN / dtex at 115 ° C. and 0.85 cN / dtex at 120 ° C. In the run evaluation, no run was generated, and it was confirmed that the heat fusion property was excellent.

  The knitted fabric unevenness evaluation of the pantyhose showed a high degree of uniformity of the knitted fabric and no unevenness. Moreover, since the set rate in wet heat was good, it finished greatly. In addition, since the stitches were excellent in stability even after washing was repeated 10 times, a beautiful knitted surface with uniform stitches was maintained.

[Example 3 ] 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 reaction kettle with a warm water jacket sealed at 80 ° C. and sealed with nitrogen gas. 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 the polyurethane elastic fiber reactor at a mass ratio of 1: 0.308, in the same manner as in Example 1. A 33 dtex polyurethane elastic fiber was produced.
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%.

When the physical properties of the finished yarn were measured in the same manner as in Example 1, the tenacity retention after heat treatment at 140 ° C. was 63%. The strength retention after heat treatment at 150 ° C. was 57%.
Further, the residual strain immediately after extending the polyurethane elastic fiber (surface layer) by 300% was 24%. The heat setting rate was 48% at 140 ° C. and 53% at 150 ° C.

SCY and a pantyhose knitted fabric were produced in the same manner as in Example 1, and wet heat set.
The heat sealing force in the SCY knitting method was 0.89 cN / dtex at 115 ° C. and 1.10 cN / dtex at 120 ° C. In the run evaluation, no run was generated, and it was confirmed that the heat fusion property was excellent.

  The evaluation of the knitted fabric unevenness of the pantyhose was a usable level although the degree of uniformity of the knitted fabric was slightly inferior. Moreover, since the set rate in wet heat was good, it finished greatly. The stability of the stitches when washed was excellent and maintained even after 10 washes.

[ Reference Example 2 ] Production of polyurethane elastic fiber by melt spinning method (low N%)
Synthetic diisocyanate of both terminal hydroxyl group prepolymers 4,4'-diphenylmethane diisocyanate (MDI) was charged in a reaction kettle with a warm water jacket at 80 ° C. sealed with nitrogen gas, and the number average molecular weight was used as a polymer diol. 49.3 parts of 1,000 polytetramethylene ether glycol (PTMG) were injected with stirring. After the reaction for 1 hour, 26.6 parts of 1,4-butanediol (BDO) was further injected as a low molecular weight diol, 1.0 part of bis (4-hydroxyphenyl) sulfone (BHPS) was added, and the mixture was stirred for 15 minutes. Thus, a hydroxyl group prepolymer at both ends was synthesized.

In parallel with this, 23.8 parts of MDI as diisocyanate was charged into 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%), add 75 parts of PTMG having a number average molecular weight of 2,000 while stirring, and stir for 40 minutes. Continuously, a both-end isocyanate group prepolymer was obtained.

Polyurethane elastic fiber melt-spun both-end isocyanate group prepolymer and both-end hydroxyl group prepolymer were continuously fed to the polyurethane elastic fiber reactor at a mass ratio of 1: 0.210, and in the same manner as in Example 1. A 33 dtex polyurethane elastic fiber was produced. The nitrogen content (N%) contained in the polyurethane elastic fiber immediately after spinning was 2.7%, and the residual isocyanate group (residual NCO%) was 0.30%.

When the physical properties of the finished yarn were measured in the same manner as in Example 1, the tenacity retention after heat treatment at 140 ° C. was 71%. The strength retention after heat treatment at 150 ° C. was 53%.
Further, the residual strain immediately after extending the polyurethane elastic fiber (surface layer) by 300% was 25%. The heat setting rate was 49% at 140 ° C. and 57% at 150 ° C.

SCY and a pantyhose knitted fabric were produced in the same manner as in Example 1, and wet heat set.
The heat sealing force in the SCY knitted fabric method was 0.44 cN / dtex at 115 ° C. and 0.82 cN / dtex at 120 ° C. In the run evaluation, no run was generated, and it was confirmed that the heat fusion property was excellent.

  The evaluation of the knitted fabric unevenness of the pantyhose was a usable level although the degree of uniformity of the knitted fabric was slightly inferior. Moreover, since the set rate in wet heat was good, it finished greatly. The stability of the stitches when washed was excellent and maintained even after 10 washes.

[Comparative Example 1]
Synthetic diisocyanate of both terminal hydroxyl group prepolymers 4,4'-diphenylmethane diisocyanate (MDI) was charged in a reaction kettle with a warm water jacket at 80 ° C. sealed with nitrogen gas, and the number average molecular weight was used as a polymer diol. 49.3 parts of 1,000 polytetramethylene ether glycol (PTMG) were injected with stirring. After the reaction for 1 hour, 26.6 parts of 1,4-butanediol (BDO) was further injected as a low molecular weight diol, 1.0 part of bis (4-hydroxyphenyl) sulfone (BHPS) was added, and the mixture was stirred for 15 minutes. Thus, a hydroxyl group prepolymer at both ends was synthesized.

In parallel with this, 29.6 parts of MDI as diisocyanate was charged in a reaction vessel with a warm water jacket at 80 ° C. sealed with nitrogen gas, and an ultraviolet absorber (2- [2-hydroxy- 3,5-bis (α, α-dimethylbenzyl) phenyl] -2Hbenzotriazole (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 a polyethylene adipene having a number average molecular weight of 2,100 with stirring. 69.1 parts of a salt (PEA) was injected, and stirring was continued for 40 minutes 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 the polyurethane elastic fiber reactor at a mass ratio of 1: 0.291 in the same manner as in Example 1. A 33 dtex polyurethane elastic fiber was produced. The nitrogen content (N%) contained in the polyurethane elastic fiber immediately after spinning was 3.2%, and the residual isocyanate group (residual NCO%) was 0.85%.

When the physical properties of the finished yarn were measured in the same manner as in Example 1, the tenacity retention after heat treatment at 140 ° C. was 100%. The strength retention after heat treatment at 150 ° C. was 93%.
Further, the residual strain immediately after extending the polyurethane elastic fiber (surface layer) by 300% was 25%. The heat set rate was 39% at 140 ° C. and 42% at 150 ° C.

SCY and a pantyhose knitted fabric were produced in the same manner as in Example 1, and wet heat set.
The heat sealing force in the SCY knitted fabric was 0.07 cN / dtex at 115 ° C. and 0.12 cN / dtex at 120 ° C. In the run evaluation, a run was generated and the heat-fusibility was inferior.

  The evaluation of the knitted fabric unevenness of the pantyhose showed high uniformity of the knitted fabric and no unevenness, but the finished size was 20% smaller than that of Example 1 and the ease of wearing was inferior to Example 1.

[Comparative Example 2]
23.5 parts of 4,4'-diphenylmethane diisocyanate (MDI) as a synthetic diisocyanate for both-terminal hydroxyl group prepolymer was charged into a reaction kettle with a warm water jacket sealed at 80 ° C. and sealed with nitrogen gas. 48.3 parts of 1,000 polytetramethylene ether glycol (PTMG) was injected with stirring. After the reaction for 1 hour, 26.6 parts of 1,4-butanediol (BDO) was further injected as a low molecular weight diol, 1.0 part of bis (4-hydroxyphenyl) sulfone (BHPS) was added, and the mixture was stirred for 15 minutes. Thus, a hydroxyl group prepolymer at both ends was synthesized.

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 75.0 parts of PTMG having a number average molecular weight of 2,000 are injected while stirring 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 the polyurethane elastic fiber reactor at a mass ratio of 1: 0.308, in the same manner as in Example 1. A 33 dtex polyurethane elastic fiber was produced. The nitrogen content (N%) contained in the polyurethane elastic fiber immediately after spinning was 3.2%, and the residual isocyanate group (residual NCO%) was 0.42%.

When the physical properties of the finished yarn were measured in the same manner as in Example 1, the strength retention after heat treatment at 140 ° C. was 64%. The strength retention after heat treatment at 150 ° C. was 62%.
Further, the residual strain immediately after stretching the polyurethane elastic fiber (surface layer) by 300% was 35%. The heat setting rate was 56% at 140 ° C and 63% at 150 ° C.

SCY and a pantyhose knitted fabric were produced in the same manner as in Example 1, and wet heat set.
The heat sealing force in the SCY knitting method was 0.14 cN / dtex at 115 ° C. and 0.24 cN / dtex at 120 ° C. In the run evaluation, a run was generated and the heat-fusibility was inferior.

  The evaluation of the knitted fabric unevenness of the pantyhose was a usable level although the degree of uniformity of the knitted fabric was slightly inferior. Finished dimensions were 15% smaller than Example 1, and ease of wearing was inferior to Example 1.

The results of Examples 1 to 3, Reference Examples 1 and 2 and Comparative Examples 1 and 2 are summarized in Table 1 below.

Claims (18)

In the method for measuring the heat fusion force by the single covering yarn knitted fabric method, a heat-fusible polyurethane elastic fiber having a heat-fusion force of 0.30 cN / dtex or more when wet-heat treated at 120 ° C. for 20 seconds,
The heat-fusible polyurethane elastic fiber is obtained by reacting a polyol, diisocyanate and at least two kinds of low molecular weight diols having 2 to 6 carbon atoms, and the content of the low molecular weight diol which is the main of the low molecular weight diols is The heat is characterized in that it is 55 mol% or more and less than 80 mol% with respect to the total low molecular weight diol, and the nitrogen content of the polyurethane elastic fiber immediately after spinning is 2.8 mass% or more and 3.4 mass% or less. Fusing polyurethane elastic fiber. In the method for measuring the heat fusion force by the single covering yarn knitted fabric method, a heat-fusible polyurethane elastic fiber having a heat-fusion force of 0.30 cN / dtex or more when wet-heat treated at 120 ° C. for 20 seconds,
The heat-fusible polyurethane elastic fiber is obtained by reacting a polyol, diisocyanate and at least two kinds of low molecular weight diols having 2 to 6 carbon atoms, and the content of the low molecular weight diol which is the main of the low molecular weight diols is The heat is characterized in that it is 80 mol% or more and less than 98 mol% with respect to the total low molecular weight diol, and the nitrogen content of the polyurethane elastic fiber immediately after spinning is 2.2 mass% or more and 3.4 mass% or less. Fusing polyurethane elastic fiber.   3. The heat-fusible polyurethane elasticity according to claim 1, wherein the heat-fusible force when wet-heat treated at 115 ° C. for 20 seconds is 0.30 cN / dtex or more in the method for measuring the heat-fusible force by the single covering yarn knitted fabric method. fiber.   The heat-sealable polyurethane elastic fiber according to any one of claims 1 to 3, wherein a residual strain immediately after stretching by 300% is 40% or less.   (I) It is obtained by reacting a two-terminal isocyanate group prepolymer obtained by reacting a first polyol and diisocyanate, and (II) a second polyol, diisocyanate and at least two low molecular weight diols having 2 to 6 carbon atoms. The heat-fusible polyurethane elastic fiber according to any one of claims 1 to 4, which is obtained by melt spinning a polymer obtained by reacting a hydroxyl group prepolymer at both terminals.   The at least two low molecular weight diols having 2 to 6 carbon atoms are composed of diols 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, The low molecular weight diol is a diol having 2 and / or 4 carbon atoms, or at least two kinds of low molecular weight diols having 2 to 6 carbon atoms are diols having 6 carbon atoms and diols having 3 and / or 5 carbon atoms The heat-fusible polyurethane elastic fiber according to any one of claims 1 to 5, wherein the main low molecular weight diol is a diol having 6 carbon atoms.   The heat-fusible polyurethane elasticity according to claim 5 or 6, wherein the first and second polyols are polyether diol and / or polyester diol, and the ratio of the polyester diol to the total polyol is 55 mol% or more and 95 mol% or less. fiber.   The heat-fusible polyurethane according to claim 5 or 6, wherein the first and second polyols are polyether diols and / or polyester diols, and the ratio of the polyether diol to the total polyol is 60 mol% or more and 100 mol% or less. Elastic fiber. The molar ratio of total diisocyanate to total amount of total polyol and total low molecular weight diol is 0.95 to 1.25, and the molar ratio of total diisocyanate to total polyol is 2.4 to 3.8, The heat-fusible polyurethane elastic fiber according to any one of claims 1 to 8 , wherein the residual isocyanate group in the yarn immediately after spinning is 0.2 to 1.0 mass%. A composite yarn which is a single covering yarn, a core spun yarn, a twisted yarn or an air entangled yarn, wherein the core yarn comprising the heat-fusible polyurethane elastic fiber according to any one of claims 1 to 9 is coated with an inelastic yarn. . A heat-fusible polyurethane elastic fiber according to any one of claims 1 to 9 , or a polyurethane elastic fiber mixed woven or knitted fabric obtained by weaving and knitting a mixture of this and other fibers. A heat-sealable polyurethane elastic fiber according to any one of claims 1 to 9 and at least one non-elastic yarn, and heat-sealable polyurethane elastic fiber and / or non-elasticity with each other by wet heat treatment. The polyurethane elastic fiber-mixed woven or knitted fabric according to claim 11 , wherein the intersection with the yarn is heat-sealed. The polyurethane according to claim 12, which is a woven fabric using warp and / or weft as a composite yarn comprising the heat-fusible polyurethane elastic fiber according to any one of claims 1 to 9 and at least one inelastic yarn. Woven knitted fabric mixed with elastic fiber. The heat-sealable polyurethane elastic fiber according to any one of claims 1 to 9 and at least one non-elastic yarn are used in the same course of a knitting machine, and the heat-sealable polyurethane elastic fiber is inserted and knitted. The polyurethane elastic fiber mixed woven or knitted fabric according to claim 12, which is a weft knitted fabric used as a plating knitting or a composite yarn with the inelastic yarn. A warp knitted fabric in which the heat-fusible polyurethane elastic fiber according to any one of claims 1 to 9 and at least one type of non-elastic yarn are inserted or knitted. The polyurethane elastic fiber mixed woven or knitted fabric according to claim 12 . Briefs, panties, shorts, undershirt, camisole, girdle, bra, spats, body suit, sanitary shorts, underwear, swimwear, leotard, resort wear, homewear, underwear, shirt, outerwear, gloves, arm cover, Medical clothing, surgical clothing, clothing for work in clean rooms, dust-proof clothing, supporters, eye masks, clothing products, disposable diapers, incontinence pads, gauze, bandages, packaging materials, packaging materials, masks, sheets, towels, handkerchiefs, hygiene products The polyurethane elastic fiber mixed woven or knitted fabric according to any one of claims 11 to 15 , which is a clothing interlining, a filter for precision filtration, an industrial wiper, a protective cover, or an industrial material. (I) a step of reacting the first polyol and diisocyanate to synthesize both terminal isocyanate group prepolymers,
(II) a step of synthesizing both terminal hydroxyl group prepolymers by reacting the second polyol, diisocyanate and at least two low molecular weight diols having 2 to 6 carbon atoms;
(III) a step of synthesizing a spinning polymer by reacting both terminal isocyanate group prepolymers and both terminal hydroxyl group prepolymers;
(IV) including a step of melt-spinning a spinning polymer, wherein the content of the main low molecular weight diol among the low molecular weight diols is 55 mol% or more and less than 80 mol% with respect to the total low molecular weight diol, A method for producing a heat-fusible polyurethane elastic fiber, characterized in that the nitrogen content of the polymer immediately after is 2.8 mass% or more and 3.4 mass% or less. (I) a step of reacting the first polyol and diisocyanate to synthesize both terminal isocyanate group prepolymers,
(II) a step of synthesizing both terminal hydroxyl group prepolymers by reacting the second polyol, diisocyanate and at least two low molecular weight diols having 2 to 6 carbon atoms;
(III) a step of synthesizing a spinning polymer by reacting both terminal isocyanate group prepolymers and both terminal hydroxyl group prepolymers;
(IV) including a step of melt-spinning a spinning polymer, and the content of the main low molecular weight diol among the low molecular weight diols is 80 mol% or more and less than 98 mol% with respect to the total low molecular weight diol, and spinning A method for producing a heat-fusible polyurethane elastic fiber, wherein the nitrogen content of the polymer immediately after is 2.2% by mass or more and 3.4% by mass or less.