JP4332627B2 - Mixed fiber, stretchable nonwoven fabric comprising the mixed fiber, and method for producing the same - Google Patents

Description

  The present invention relates to a mixed fiber containing a fiber A made of a polymer containing a thermoplastic polyurethane elastomer and a fiber B made of a thermoplastic polymer other than the thermoplastic polyurethane elastomer, an elastic nonwoven fabric made of the mixed fiber, and a method for producing the same About. Moreover, this invention relates to the laminated body and sanitary material containing this elastic nonwoven fabric.

  There have been some proposals for stretchable nonwoven fabrics using thermoplastic polyurethane elastomers (hereinafter sometimes abbreviated as “TPU”), which have high elastic properties, small residual strain and excellent ventilation. It is used for applications such as clothing, sanitary materials, and sports materials.

  In Patent Document 1, as one of the problems when a nonwoven fabric is produced by a spunbond method using a thermoplastic elastomer, the property “easy to stick”, which is a feature of the thermoplastic elastomer, is cited. It points out the possibility of filaments adhering to each other by turbulent air flow when forming nonwoven fabrics by the spunbond method. It is also described that this “easiness of sticking” becomes particularly troublesome when the web is wound on a roll. Another problem is that the strand breaks or has poor elasticity during extrusion and / or drawing.

  In order to solve such a problem, at least two polymers of low elasticity and high elasticity are used to form a strand, and the low elasticity polymer constitutes at least a part of the peripheral surface of the strand as described above. Solves the problem. Specifically, Example 10 of Patent Document 1 discloses that spunbond molding was performed using TPU as a core and linear low density polyethylene (hereinafter also abbreviated as “LLDPE”) as a sheath. Has been. In this case, it is disclosed that the combined web can be handled and can be wound and subsequently unwound. However, when the fiber is thinned in this method, yarn breakage is likely to occur, and there is a problem that a nonwoven fabric having a desired fiber diameter cannot be obtained.

  Patent Document 2 discloses a stretchable nonwoven fabric made of a composite fiber of crystalline polypropylene and a thermoplastic elastomer and having an excellent texture. Patent Document 2 discloses a stretchable nonwoven fabric (Example 6) made of a concentric core-sheath composite fiber using 50% by weight of urethane elastomer for the core and 50% by weight of polypropylene for the sheath, and 50% by weight of urethane elastomer. And a stretchable nonwoven fabric (Example 8) comprising 50% by weight of polypropylene and a composite fiber having a fiber cross-sectional shape of 6 parts. These nonwoven fabrics have an elongation recovery rate of about 75% at 20% elongation and are disclosed to have excellent texture. However, when used as clothing, hygiene materials, and sports materials, these nonwoven fabrics have further stretch properties. There is a need for improvement.

Patent Document 3 discloses a nonwoven fabric composed of mixed fibers in which two types of fibers composed of different polymers are mixed. It is disclosed that such a nonwoven fabric has characteristics of different materials, for example, good tactile sensation and excellent stretchability. However, Patent Document 3 does not specifically disclose the polyurethane elastomer. In addition, as shown in Comparative Example 4 of the present specification, even a non-woven fabric made of a mixed fiber containing a fiber made of polyurethane elastomer and a fiber made of polypropylene is inferior in stretchability and touch, and further in spinnability. There was a problem of being inferior.
JP 2002-522653 A JP-A-9-291454 JP 2002-242069 A

  The present invention is intended to solve the problems associated with the prior art as described above, and is excellent in touch, heat sealability and productivity obtained from a well-spun mixed fiber and the mixed fiber. An object of the present invention is to provide a stretchable nonwoven fabric having a small residual strain and high elasticity, and a laminate and a sanitary material including the stretchable nonwoven fabric. Another object of the present invention is to provide a method for producing such a stretchable nonwoven fabric by spunbond molding.

  The present inventor has eagerly studied to solve the above problems, and by using a thermoplastic polyurethane elastomer having a specific range of solidification start temperature and a polar solvent insoluble content, spinnability (formability) due to “ease of sticking”. The present inventors have found that a non-woven fabric having excellent tactile sensation and high elasticity can be obtained, and the present invention has been completed.

  That is, the mixed fiber according to the present invention has a solidification start temperature measured by a differential scanning calorimeter (DSC) of 65 ° C. or more, and a 100 μm aperture is attached to a particle size distribution measuring apparatus based on the pore electrical resistance method. A fiber A composed of a polymer A containing a thermoplastic polyurethane elastomer whose number of polar solvent-insoluble particles to be measured is 3 million pieces / g or less, and a fiber B composed of a thermoplastic polymer B other than the thermoplastic polyurethane elastomer. It is characterized by including.

  The fiber B is preferably a non-stretchable fiber, and the polymer A preferably contains 50% by weight or more of the thermoplastic polyurethane elastomer.

The thermoplastic polyurethane elastomer has a total heat of fusion (a) determined from an endothermic peak having a peak temperature in the range of 90 ° C. or more and 140 ° C. or less as measured by a differential scanning calorimeter (DSC), and a peak temperature of 140. The total amount of heat of fusion (b) determined from the endothermic peak in the range of more than 220 ° C. and less than 220 ° C. is the following formula (1)
a / (a + b) × 100 ≦ 80 (1)
It is preferable to satisfy the relationship.

  The stretchable nonwoven fabric according to the present invention is characterized by being obtained by depositing the mixed fibers in a web shape, partially fusing the deposit, and then drawing.

  The laminate according to the present invention includes at least one layer composed of the stretchable nonwoven fabric, and the sanitary material according to the present invention includes the stretchable nonwoven fabric.

The method for producing a stretchable nonwoven fabric according to the present invention includes:
(I) Polar solvent insoluble content measured by attaching a 100 μm aperture to a particle size distribution measuring apparatus based on the pore electrical resistance method, having a solidification start temperature of 65 ° C. or higher measured by a differential scanning calorimeter (DSC) A step of independently melting the polymer A containing a thermoplastic polyurethane elastomer having a particle number of 3 million particles / g or less and the thermoplastic polymer B other than the thermoplastic polyurethane elastomer,
(II) the step of extruding the polymer A and the polymer B independently from different nozzles arranged in the same die and spinning to deposit the mixed fibers in a web;
(III) a step of partially fusing the deposit obtained in the previous step;
(IV) It is characterized by comprising a step of stretching the deposit partially fused in the previous step.

  The mixed fiber according to the present invention is a well spun fiber. The stretchable nonwoven fabric according to the present invention is a highly elastic nonwoven fabric having excellent tactile sensation, heat sealability and productivity, low residual strain, and high elasticity. Furthermore, the laminate and the sanitary material according to the present invention are excellent in the adhesion between the layer made of the stretchable nonwoven fabric and the other layers, particularly the adhesion by heat sealing.

[Mixed fiber and stretchable nonwoven fabric]
The mixed fiber according to the present invention includes a fiber A composed of a polymer A containing a thermoplastic polyurethane elastomer having a specific range of solidification start temperature and a polar solvent insoluble content, and a fiber B composed of a thermoplastic polymer B other than the thermoplastic polyurethane elastomer. Containing.

  The stretchable nonwoven fabric according to the present invention can be obtained by depositing the mixed fiber in a web shape, partially fusing the deposit, and then drawing.

<Thermoplastic polyurethane elastomer>
The thermoplastic polyurethane elastomer (TPU) used in the present invention has a solidification start temperature of 65 ° C or higher, preferably 75 ° C or higher, and most preferably 85 ° C or higher. The upper limit of the solidification start temperature is preferably 195 ° C. Here, the solidification start temperature is a value measured using a differential scanning calorimeter (DSC), and the temperature of the TPU is increased to 230 ° C. at 10 ° C./min, held at 230 ° C. for 5 minutes, and then 10 ° C. This is the starting temperature of the exothermic peak derived from the solidification of TPU that occurs when the temperature is lowered at a rate of 1 minute. When the solidification start temperature is 65 ° C. or higher, it is possible to suppress molding defects such as fusion between fibers, yarn breakage, and resin lump when performing spunbond molding, and molding is performed during hot embossing. The nonwoven fabric can be prevented from being wound around the embossing roller. Moreover, the obtained nonwoven fabric also has little stickiness, and is suitably used for materials that come into contact with the skin, such as clothing, sanitary materials, and sports materials. On the other hand, the moldability can be improved by setting the solidification start temperature to 195 ° C. or lower. In addition, the solidification start temperature of the formed fiber tends to be higher than the solidification start temperature of the TPU used for this.

  In order to adjust the solidification start temperature of TPU to 65 ° C or higher, the polyol, isocyanate compound and chain extender used as the raw material of TPU are each selected to have an optimal chemical structure, and the amount of hard segment It needs to be adjusted. Here, the hard segment amount is a weight percent (% by weight) obtained by dividing the total weight of the isocyanate compound and chain extender used for the production of TPU by the total amount of polyol, isocyanate compound and chain extender and multiplying by 100. ) Value. The amount of hard segment is preferably 20 to 60% by weight, more preferably 22 to 50% by weight, and most preferably 25 to 48% by weight.

  The TPU has a polar solvent-insoluble particle number of 3 million particles / g or less, preferably 2.5 million particles or less, and most preferably 2 million particles or less. Here, the polar solvent-insoluble matter in TPU is mainly a lump such as fish eye or gel generated during the production of TPU, components derived from TPU hard segment aggregates, and hard segments and / or Alternatively, it is a component generated by a chemical reaction between the raw materials constituting the TPU, such as a component in which the soft segment is crosslinked by an allophanate bond, a burette bond, or the like.

The number of particles insoluble in the polar solvent is determined based on the insoluble content obtained by dissolving TPU in a dimethylacetamide solvent (hereinafter abbreviated as “DMAC”). It is a value measured by wearing. When a 100 μm aperture is attached, the number of particles having a size of 2 to 60 μm in terms of uncrosslinked polystyrene can be measured. The present inventor has found that particles having a size in this range show a deep relationship with the spinning stability of the mixed fiber using TPU and the quality of the stretchable nonwoven fabric. That is, by setting the number of particles insoluble in the polar solvent to 3 million or less with respect to 1 g of TPU, within the above TPU solidification start temperature range, there are problems such as an increase in fiber diameter distribution and yarn breakage during spinning. It can be avoided. Moreover, the nonwoven fabric shape | molded using such TPU can make the fiber diameter equivalent to the fiber diameter of a textile fabric, and since it is excellent in tactile sense, it can be used suitably for a sanitary material etc., for example. In addition, the filter installed inside the extruder for filtering impurities and the like is not easily clogged, and the frequency of adjustment and maintenance of the equipment is reduced, which is industrially preferable.

  The TPU having a small amount of polar solvent insolubles can be obtained by filtration after a polymerization reaction of a polyol, an isocyanate compound and a chain extender, as will be described later.

The TPU is a sum of the heat of fusion (a) obtained from an endothermic peak having a peak temperature in the range of 90 ° C. or more and 140 ° C. or less as measured by a differential scanning calorimeter (DSC), and the peak temperature exceeds 140 ° C. The total amount of heat of fusion (b) determined from the endothermic peak in the range of 220 ° C. or less is the following formula (1)
a / (a + b) × 100 ≦ 80 (1)
It is preferable to satisfy the relationship
Following formula (2)
a / (a + b) × 100 ≦ 70 (2)
It is more preferable to satisfy the relationship of
Following formula (3)
a / (a + b) × 100 ≦ 55 (3)
It is most preferable to satisfy this relationship.

  Here, “a / (a + b) × 100” means the ratio of heat of fusion of hard domains of TPU (unit:%). When the ratio of heat of fusion of TPU hard domains is 80% or less, the strength and stretchability of fibers, particularly fibers and nonwoven fabrics in spunbond molding, are improved. In the present invention, the lower limit of the ratio of heat of fusion of the hard domain of TPU is preferably about 0.1%.

The TPU preferably has a melt viscosity of 100 to 3000 Pa · s, more preferably 200 to 2000 Pa · s, and most preferably 1000 to 1500 Pa · s under the conditions of a temperature of 200 ° C. and a shear rate of 100 sec ⁻¹ . Here, the melt viscosity is a value measured by a capillograph (made by Toyo Seiki Co., Ltd., having a nozzle length of 30 mm and a diameter of 1 mm).

  Further, the TPU has a moisture value of preferably 350 ppm or less, more preferably 300 ppm or less, and most preferably 150 ppm or less. By setting the moisture value to 350 ppm or less, it is possible to suppress the mixing of bubbles into the strands or the occurrence of yarn breakage in forming a nonwoven fabric with a large spunbond molding machine.

<Method for producing thermoplastic polyurethane elastomer>
As described above, the thermoplastic polyurethane elastomer used in the present invention is produced by selecting polyols, isocyanate compounds, and chain extenders having optimum chemical structures. As a method for producing TPU, (i) a method in which an isocyanate group-terminated prepolymer (hereinafter simply referred to as “prepolymer”) obtained by reacting a polyol and an isocyanate compound in advance and a chain extender are reacted (hereinafter referred to as “ And (ii) a method in which a polyol and a chain extender are mixed in advance, and then this mixture is reacted with an isocyanate compound (hereinafter referred to as “one-shot method”). Among these production methods, it is preferable to produce TPU by a prepolymer method from the viewpoint of mechanical properties and quality of the obtained TPU.

  In the prepolymer method, a polyol and an isocyanate compound are stirred and mixed at a reaction temperature of about 40 to 250 ° C. for about 30 seconds to about 8 hours in the presence of an inert gas to produce a prepolymer. Next, the prepolymer and chain extension in such a proportion that the isocyanate index is preferably in the range of 0.9 to 1.2, more preferably 0.95 to 1.15, and even more preferably 0.97 to 1.08. Stir the agent at high speed and mix thoroughly. The temperature at which the prepolymer and the chain extender are mixed and polymerized is appropriately determined depending on the melting point of the chain extender used and the viscosity of the prepolymer, but is usually about 80 to 300 ° C, preferably 80 to 260 ° C. Most preferably, it is in the range of 90-220 ° C. The polymerization time is preferably about 2 seconds to 1 hour.

  Similarly for the one-shot method, the polyol and the chain extender are premixed and defoamed, and the mixture and the isocyanate compound are mixed at 40 ° C. to 280 ° C., more preferably 100 ° C. to 260 ° C. for 30 seconds. The polymerization reaction is advanced by stirring and mixing for about 1 hour. The isocyanate index in the one-shot method is preferably in the same range as in the prepolymer method.

<TPU production equipment>
The TPU manufacturing apparatus is an apparatus for continuously manufacturing a thermoplastic polyurethane elastomer by a reactive extrusion molding method, and includes a raw material tank section, a mixing section, a static mixer section, and a pelletizing section.

  The raw material tank section includes an isocyanate compound storage tank, a polyol storage tank, and a chain extender storage tank. Each storage tank is connected to a high-speed stirrer or a static mixer section, which will be described later, via each supply line, and a gear pump and a flow meter are interposed downstream of each supply line.

  The mixing unit includes mixing means such as a high-speed stirrer. The high-speed stirrer is not particularly limited as long as the above-described raw materials can be stirred and mixed at high speed. However, when the stirring blade in the stirring tank has a blade diameter of 4 cmφ and a peripheral length of 12 cm, for example, 300 to 5000 revolutions / minute (circumferential speed). 100 to 600 m / min), preferably 1000 to 3500 revolutions / min (peripheral speed 120 to 420 m / min). The high-speed stirrer preferably includes a heater (or jacket) and a temperature sensor, and can control the temperature in the stirring tank by controlling the heater based on the temperature detected by the temperature sensor.

  Further, the mixing unit may be provided with a reaction pot for temporarily retaining a mixture of reaction raw materials mixed by a high-speed stirrer to promote prepolymerization, if necessary. Such a reaction pot is preferably provided with a temperature adjusting means. The reaction pot is preferably connected between the high-speed stirrer and the most upstream first static mixer in the static mixer section.

  The static mixer section is preferably configured by connecting a plurality of static mixers (static mixers) in series. Each static mixer (hereinafter, when each static mixer is distinguished, the first static mixer 1, the second static mixer 2,... The nth static mixer from the upstream side toward the downstream side in the flow direction of the reaction raw materials. The shape of the internal mixer member is not particularly limited. For example, “Progress in Chemical Engineering, Vol. 24, Stirring / Mixing” (Edited by the Society of Chemical Engineering, Tokai Branch, October 20, 1990) FIG. Various shapes such as Company-N type, Company-T type, Company-S type, and Company-T type described in 10.1.1 can be used. Preferably, the right element and the left element are alternately arranged, and a straight pipe may be provided between the static mixers as necessary.

  Each static mixer has a tube length of, for example, 0.13 to 3.6 m, preferably 0.3 to 2.0 m, more preferably 0.5 to 1.0 m, and an inner diameter of, for example, 10 to 300 mmφ, preferably The diameter is 13 to 150 mmφ, more preferably 15 to 50 mmφ, and the tube length / inner diameter ratio (hereinafter referred to as L / D) is usually 3 to 25, preferably 5 to 15. In addition, each static mixer has at least a contact portion with the reaction raw material formed of a substantially non-metallic material such as fiber reinforced plastic (FRP), or a surface of the contact portion with the reaction raw material, for example, polytetra It is preferable to use what is coated with a fluorine-based resin such as fluoroethylene. By using a static mixer in which the contact portion with the reaction raw material is substantially formed of a non-metallic material, it is possible to effectively prevent the generation of polar solvent insolubles in TPU. As such a static mixer, specifically, a metal static mixer whose inner wall is protected with a tube made of a fluororesin such as polytetrafluoroethylene, and a commercially available MX series manufactured by Noritake Company Limited, etc. Can be mentioned.

  Further, each static mixer is preferably provided with a heater (or jacket) and a temperature sensor individually, and can control the temperature independently of the mixer by controlling the heater based on the temperature detected by the temperature sensor. Thereby, the tube temperature of each static mixer can be changed according to the composition of the reaction raw material, and the amount of catalyst can be reduced to produce TPU under optimum reaction conditions.

  The first static mixer 1 on the most upstream side of the static mixer section is connected to a high-speed stirrer in the mixing section or the reaction pot, and the n-th static mixer n on the most downstream side in the static mixer section is a strand die of the pelletizing section described later. Or connected to a single screw extruder. The number of connected static mixers can be appropriately determined depending on the purpose and application of the TPU, the raw material composition, and the like. For example, each static mixer is connected so that the total length of the static mixer section is usually 3 to 25 m, preferably 5 to 20 m, and in terms of the number of connections, for example, 10 to 50 stations, preferably 15 to 35 stations are connected. . Between each static mixer, you may adjust a flow volume by interposing a gear pump suitably.

  The pelletizing unit may be constituted by a known pelletizer such as an underwater cutting device, or may be provided with a strand die and a cutter.

  A single-screw extruder for further kneading the reaction product flowing out from the static mixer section may be provided between the static mixer section and the pelletizing section.

<TPU manufacturing method>
The TPU used in the present invention can be manufactured using the TPU manufacturing apparatus as described above. For example, these reaction raw materials are subjected to a polymerization reaction while a mixture in which at least an isocyanate compound and a polyol are mixed in advance and a chain extender are passed through a static mixer. In particular, it is preferable that the isocyanate compound and the polyol are sufficiently stirred and mixed with a high-speed stirrer, and the mixture and the chain extender are further stirred and mixed with a high-speed stirrer, and then subjected to a polymerization reaction in a static mixer. Moreover, after mixing an isocyanate compound and a polyol and making these react, a prepolymer is prepared and this prepolymer and a chain extender are mixed with a high-speed stirrer, it is also possible to carry out a polymerization reaction in a static mixer.

In the mixture, an isocyanate compound and a polyol are mixed in a stirring tank, and the residence time is usually 0.05 to 0.5 minutes, preferably 0.1 to 0.4 minutes, and the temperature is usually 60 to 150 ° C., preferably 80 to Prepared by high-speed stirring at 140 ° C. In order to promote prepolymerization, when this mixture is retained in a reaction pot, the residence time is usually 0.1 to 60.
Minutes, preferably 1 to 30 minutes, and the temperature at this time is usually 80 to 150 ° C, preferably 90 to 140 ° C.

  The mixture thus prepared and the chain extender are supplied to a static mixer and subjected to a polymerization reaction. The mixture and the chain extender may be independently supplied to the static mixer, or may be supplied to the static mixer after previously mixing with a high-speed stirrer. Alternatively, a prepolymer may be produced in advance by reacting an isocyanate compound and a polyol, and the prepolymer and a chain extender may be supplied to a static mixer to cause a polymerization reaction. The temperature in the static mixer is usually 100 to 300 ° C, preferably 150 to 280 ° C. The passing speed of the reaction raw materials and reaction products is set to 10 to 200 kg / h, preferably 30 to 150 kg / h.

  In addition to the method described above, the TPU used in the present invention is prepared by, for example, thoroughly stirring and mixing an isocyanate compound, a polyol and a chain extender in advance with a high-speed stirrer, and continuously flowing this mixture onto a belt and heating it. TPU can also be produced by polymerization.

  By producing TPU by these production methods, it is possible to obtain TPU with little polar solvent-insoluble matter such as fish eye. Moreover, a polar solvent insoluble content can be reduced by filtering obtained TPU. For example, after the TPU pellets are sufficiently dried, the fish eye can be filtered by passing through an extruder equipped with a metal mesh, metal nonwoven fabric or polymer filter at the tip. The lower limit of the amount of polar solvent insoluble in the TPU thus obtained is about 30,000 / g. The extruder is preferably a single-screw or multi-screw extruder. The mesh size of the metal mesh is usually 100 mesh or more, preferably 500 mesh or more, more preferably 1000 mesh or more. Further, it is preferable to use a plurality of metal meshes having the same mesh size or different mesh sizes. Examples of polymer filters include Fuji Deuplex Polymer Filter System (Fuji Filter Industry Co., Ltd.), Asuka Polymer Filter System (Asuka Industry Co., Ltd.), and Dena Filter (Nagase Sangyo Co., Ltd.). Can be mentioned.

  The TPU obtained by the above method may be pulverized and refined using a cutter, a pelletizer or the like, and then processed into a desired shape using an extrusion molding machine or an injection molding machine.

<Polyol>
The polyol used for the production of the TPU is a polymer having two or more hydroxyl groups in one molecule, and examples thereof include polyoxyalkylene polyol, polytetramethylene ether glycol, polyester polyol, polycaprolactone polyol, and polycarbonate diol. it can. These polyols may be used alone or in combination of two or more. Of these polyols, polyoxyalkylene polyol, polytetramethylene ether glycol, and polyester polyol are preferable.

  These polyols are preferably subjected to a heat-depressurized dehydration treatment to reduce moisture. The water content of these polyols is preferably 0.05% by weight or less, more preferably 0.03% by weight or less, and still more preferably 0.02% by weight or less.

(Polyoxyalkylene polyol)
Examples of the polyoxyalkylene polyol include polyoxyalkylene glycols obtained by addition polymerization of alkylene oxides such as propylene oxide, ethylene oxide, butylene oxide, and styrene oxide to one or more dihydric alcohols having a relatively low molecular weight. It is done. The polymerization catalyst used at this time is preferably an alkali metal compound such as cesium hydroxide or rubidium hydroxide, or a compound having a P = N bond.

  Of the alkylene oxides, propylene oxide and ethylene oxide are particularly preferably used. Moreover, when using 2 or more types of alkylene oxides, it is desirable that propylene oxide is 40 weight% or more of the total amount, More preferably, 50 weight% or more. By using the alkylene oxide containing the above proportion of propylene oxide, the content of the oxypropylene group in the polyoxyalkylene polyol can be 40% by weight or more.

  In order to improve the durability and mechanical properties of TPU, the primary hydroxylation rate at the molecular terminals of the polyoxyalkylene polyol is desirably 50 mol% or more, more preferably 60 mol% or more. In order to improve the primary hydroxylation rate, it is preferable to copolymerize ethylene oxide at the molecular terminals.

  The number average molecular weight of the polyoxyalkylene polyol used for the production of the TPU is preferably in the range of 200 to 8000, more preferably 500 to 5000. From the viewpoint of lowering the glass transition point of TPU and improving flow characteristics, it is preferable to produce TPU by mixing two or more polyoxyalkylene polyols having different molecular weights and oxyalkylene group contents. Moreover, it is preferable that the polyoxyalkylene polyol contains a small amount of monool having an unsaturated group at the molecular end produced by a side reaction of propylene oxide addition polymerization. The monool content in the polyoxyalkylene polyol is represented by the total degree of unsaturation described in JIS K-1557. The total unsaturation degree of the polyoxyalkylene polyol is preferably 0.03 meq / g or less, more preferably 0.02 meq / g or less. When the total degree of unsaturation is greater than 0.03 meq / g, the heat resistance and durability of the TPU tend to decrease. From the viewpoint of industrial production of polyoxyalkylene polyol, the lower limit of the total unsaturation is preferably about 0.001 meq / g.

(Polytetramethylene ether glycol)
In the present invention, polytetramethylene ether glycol (hereinafter abbreviated as “PTMEG”) obtained by ring-opening polymerization of tetrahydrofuran can also be used as the polyol. The number average molecular weight of PTMEG is preferably about 250 to 4000, particularly preferably about 250 to 3000.

(Polyester polyol)
Examples of the polyester polyol include polyester polyols obtained by condensation polymerization of one or more kinds of low molecular weight polyols and one or more kinds of carboxylic acids such as low molecular weight dicarboxylic acids and oligomer acids.

  Examples of the low molecular weight polyol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, triglyceride, Examples include methylolpropane, 3-methyl-1,5-pentanediol, hydrogenated bisphenol A, and hydrogenated bisphenol F. Examples of the low molecular weight dicarboxylic acid include glutaric acid, adipic acid, sebacic acid, terephthalic acid, isophthalic acid, and dimer acid. Specific examples include polyethylene butylene adipate polyol, polyethylene adipate polyol, polyethylene propylene adipate polyol, and polypropylene adipate polyol.

  The number average molecular weight of the polyester polyol is preferably about 500 to 4000, and particularly preferably about 800 to 3000.

(Polycaprolactone polyol)
The polycaprolactone polyol can be obtained by ring-opening polymerization of ε-caprolactone.

(Polycarbonate diol)
Examples of the polycarbonate diol include polycarbonate diols obtained by a condensation reaction between a dihydric alcohol such as 1,4-butanediol and 1,6-hexanediol and a carbonate compound such as dimethyl carbonate, diethyl carbonate, and diphenyl carbonate. The number average molecular weight of the polycarbonate diol is preferably about 500 to 3,000, particularly preferably about 800 to 2,000.

<Isocyanate compound>
Examples of the isocyanate compound used in the production of TPU include aromatic, aliphatic, and alicyclic compounds having two or more isocyanate groups in one molecule.

(Aromatic polyisocyanate)
As aromatic polyisocyanate, isomer mixture of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, weight ratio (2,4-isomer: 2,6-isomer) 80:20 ( TDI-80 / 20), weight ratio (2,4-isomer: 2,6-isomer) 65:35 tolylene diisocyanate isomer mixture (TDI-65 / 35); 4,4′-diphenylmethane diisocyanate, 2 , 4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, and any isomer mixture of these diphenylmethane diisocyanates; toluylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, paraphenylene diisocyanate, naphthalene diisocyanate, etc. And the like.

(Aliphatic polyisocyanate)
Examples of the aliphatic polyisocyanate include ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, 2,2′-dimethylpentane diisocyanate, and 2,2,4-trimethylhexane diisocyanate. , Decamethylene diisocyanate, butene diisocyanate, 1,3-butadiene-1,4-diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 1,6,11-undecamethylene triisocyanate, 1,3,6-hexa Methylene triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 2,5,7-trimethyl-1,8-diisocyanate Anate-5-isocyanate methyl octane, bis (isocyanate ethyl) carbonate, bis (isocyanate ethyl) ether, 1,4-butylene glycol dipropyl ether-ω, ω′-diisocyanate, lysine isocyanate methyl ester, lysine triisocyanate, 2- Examples thereof include isocyanate ethyl-2,6-diisocyanate hexanoate, 2-isocyanatopropyl-2,6-diisocyanate hexanoate, and bis (4-isocyanate-n-butylidene) pentaerythritol.

(Alicyclic polyisocyanate)
Examples of the alicyclic polyisocyanate include isophorone diisocyanate, bis (isocyanate methyl) cyclohexane, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, 2,2′-dimethyldicyclohexylmethane diisocyanate, dimer acid diisocyanate, and 2,5-diisocyanate. Methyl-bicyclo [2.2.1] -heptane, 2,6-diisocyanatomethyl-bicyclo [2.2.1] -heptane, 2-isocyanatemethyl-2- (3-isocyanatopropyl) -5-isocyanatemethyl- Bicyclo [2.2.1] -heptane, 2-isocyanatomethyl-2- (3-isocyanatopropyl) -6-isocyanatomethyl-bicyclo [2.2 .1] -Heptane, 2-isocyanatomethyl-3- (3-isocyanatopropyl) -5- (2-isocyanatoethyl) -bicyclo [2.2.1] -heptane, 2-isocyanatomethyl-3- (3- Isocyanatopropyl) -6- (2-isocyanatoethyl) -bicyclo [2.2.1] -heptane, 2-isocyanatomethyl-2- (3-isocyanatopropyl) -5- (2-isocyanatoethyl) -bicyclo [2 2.1] -heptane, 2-isocyanatomethyl-2- (3-isocyanatopropyl) -6- (2-isocyanatoethyl) -bicyclo [2.2.1] -heptane, and the like.

  Further, as the polyisocyanate, modified isocyanates such as urethane modified products, carbodiimide modified products, uretoimine modified products, biuret modified products, allophanate modified products, and isocyanurate modified products of polyisocyanate can be used.

  Among these polyisocyanates, 4,4′-diphenylmethane diisocyanate (hereinafter abbreviated as “MDI”), hydrogenated MDI (dicyclohexylmethane diisocyanate, hereinafter abbreviated as “HMDI”), paraphenylene diisocyanate (hereinafter “PPDI”). ), Naphthalene diisocyanate (hereinafter abbreviated as “NDI”), hexamethylene diisocyanate (hereinafter abbreviated as “HDI”), isophorone diisocyanate (hereinafter abbreviated as “IPDI”), 2,5-diisocyanate methyl-bicyclo [ 2.2.1] -heptane (hereinafter abbreviated as “2,5-NBDI”), 2,6-diisocyanatomethyl-bicyclo [2.2.1] -heptane (hereinafter referred to as “2,6-NBDI”) (Abbreviated) is preferably used. More preferably, MDI, HDI, HMDI, PPDI, 2,5-NBDI, 2,6-NBDI, etc. are used. Further, preferred urethane-modified products, carbodiimide-modified products, uretoimine-modified products, and isocyanurate-modified products of these preferred diisocyanates are also preferably used.

<Chain extender>
The chain extender used for the production of TPU is preferably an aliphatic, aromatic, heterocyclic or alicyclic low molecular weight polyol having two or more hydroxyl groups in one molecule. It is preferable that the chain extender is sufficiently dehydrated by heating to reduce moisture. The water content of the chain extender is preferably 0.05% by weight or less, more preferably 0.03% by weight or less, and still more preferably 0.02% by weight or less.

  Examples of the aliphatic polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, trimethylolpropane, and the like. It is done. Examples of aromatic, heterocyclic or alicyclic polyols include paraxylene glycol, bis (2-hydroxyethyl) terephthalate, bis (2-hydroxyethyl) isophthalate, 1,4-bis (2-hydroxyethoxy). ) Benzene, 1,3-bis (2-hydroxyethoxy) benzene, resorcin, hydroquinone, 2,2′-bis (4-hydroxycyclohexyl) propane, 3,9-bis (1,1-dimethyl-2-hydroxyethyl) ) -2,4,8,10-tetraoxaspiro [5.5] undecane, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol and the like.

  These chain extenders may be used individually by 1 type, and 2 or more types may be mixed and used for them.

<Catalyst>
When manufacturing said TPU, you may add the well-known catalyst used when manufacturing polyurethanes, such as an organometallic compound. Of the known catalysts, organometallic compounds are preferred, such as tin acetate, tin octylate, tin oleate, tin laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, lead octoate, lead naphthenate, Examples thereof include nickel naphthenate and cobalt naphthenate. These catalysts may be used individually by 1 type, and may mix and use 2 or more types arbitrarily. The amount of the catalyst is usually 0.0001 to 2.0 parts by weight, preferably 0.001 to 1.0 parts by weight with respect to 100 parts by weight of the polyol.

<Additives>
It is preferable to add a heat-resistant stabilizer or a light-resistant stabilizer to the TPU used in the present invention. These stabilizers can be added either during the production of TPU or after the production, but are preferably dissolved in the reaction raw material in advance during the production of TPU.

  Examples of the heat resistance stabilizer include hindered phenol antioxidants, phosphorus heat stabilizers, lactone heat stabilizers, sulfur heat stabilizers, and the like. More specifically, for example, IRGANOX 1010, 1035, 1076, 1098, 1135, 1222, 1425WL, 1520L, 245, 3790, 5057, IRGAFOS168, 126, HP-136 (and above) Trade name, manufactured by Ciba Specialty Chemicals Co., Ltd.) and the like are preferably used.

  Examples of the light-resistant stabilizer include benzotriazole-based UV absorbers, triazine-based UV absorbers, benzophenone-based UV absorbers, benzoate-based light stabilizers, hindered amine-based light stabilizers, and the like. More specifically, for example, TINUVIN P, 234, 326, 327, 328, 329, 571, 144, 765, B75 (above, trade name, Ciba Specialty Chemicals Co., Ltd. And the like) are preferably used.

  These heat stabilizers and light stabilizers are each preferably added in an amount of 0.01 to 1% by weight, more preferably 0.1 to 0.8% by weight, based on TPU.

  Moreover, you may add a hydrolysis inhibitor, a mold release agent, a coloring agent, a lubricant, a rust preventive agent, a filler, etc. to the said TPU as needed.

<Polymer A>
As the polymer A for forming the fiber A, the above-mentioned thermoplastic polyurethane elastomer can be used alone, but other thermoplastic polymers can be included as necessary within the range not impairing the object of the present invention. . When the polymer A contains another thermoplastic polymer, the content of TPU is preferably 50% by weight or more, more preferably 65% by weight or more, and most preferably 80% by weight or more. By using Polymer A with a TPU content of 50% by weight or more, a stretchable nonwoven fabric with sufficient elasticity and low residual strain rate can be obtained. For example, it is necessary to repeatedly stretch fabrics, hygiene materials, sports materials, etc. It can be preferably used as a material.

(Other thermoplastic polymers)
The other thermoplastic polymer is not particularly limited as long as it can produce a nonwoven fabric. For example, styrene elastomers; polyolefin elastomers; vinyl chloride elastomers; polyesters; ester elastomers; polyamides; amide elastomers; polyolefins such as polyethylene, polypropylene, and polystyrene;

  Styrenic elastomers include diblock and triblock copolymers based on polystyrene blocks and butadiene rubber blocks or isoprene rubber blocks. The rubber block may be unsaturated or fully hydrogenated. As the styrene elastomer, KRATON polymer (trade name, manufactured by Shell Chemical Co., Ltd.), SEPTON (trade name, manufactured by Kuraray Co., Ltd.), TUFTEC (trade name, manufactured by Asahi Kasei Kogyo Co., Ltd.), Rheostomer (trade name, Riken Technos Co., Ltd.).

  Examples of polyolefin elastomers include ethylene / α-olefin copolymers and propylene / α-olefin copolymers. For example, TAFMER (trade name, manufactured by Mitsui Chemicals Co., Ltd.), Engage (trade name, manufactured by DuPont Dow Elastomers) which is an ethylene-octene copolymer, CATALOOY (trade name, manufactured by Montell Co., Ltd.) which is a crystalline olefin copolymer) Etc.

  Examples of the vinyl chloride elastomer include Leonil (trade name, manufactured by Riken Technos Co., Ltd.) and Posmeal (trade name, manufactured by Shin-Etsu Polymer Co., Ltd.).

  Examples of the ester-based elastomer include HYTREL (trade name, manufactured by EI DuPont Co., Ltd.) and perprene (trade name, manufactured by Toyobo Co., Ltd.).

  Examples of the amide elastomer include PEBAX (trade name, Atofina Japan Co., Ltd.).

  Also, DUMILAN (trade name, manufactured by Mitsui Takeda Chemical Co., Ltd.), which is an ethylene / vinyl acetate / vinyl alcohol copolymer, and NUCREL (trade name, Mitsui DuPont Polychemical, which is an ethylene / (meth) acrylic acid copolymer resin) ELVALOY (trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd.), which is an ethylene-acrylic acid ester-CO terpolymer, can also be used as other thermoplastic polymers.

  Such other thermoplastic polymers may be spun by pelletizing and blending with TPU in the molten state, or may be spun by blending with TPU in the pellet state.

(Additive)
Polymer A used in the present invention includes various stabilizers such as heat stabilizer and weather stabilizer; antistatic agent, slip agent, antifogging agent, lubricant, dye, pigment, natural oil, synthetic oil, wax, etc. can do.

  Examples of the stabilizer include an antioxidant such as 2,6-di-t-butyl-4-methylphenol (BHT); tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxy Phenyl) propionate] methane, β- (3,5-di-t-butyl-4-hydroxyphenyl) propionic acid alkyl ester, 2,2′-oxamide bis [ethyl-3- (3,5-di-t-butyl) -4-hydroxyphenyl)] propionate, Irganox 1010 (hindered phenolic antioxidant: trade name) and other phenolic antioxidants; fatty acid metal salts such as zinc stearate, calcium stearate, calcium 1,2-hydroxystearate Glycerin monostearate, glycerin distearate, pentaerythritol monostearate And polyhydric alcohol fatty acid esters such as rate, pentaerythritol distearate and pentaerythritol tristearate. These may be used alone or in combination of two or more.

<Thermoplastic polymer B>
The thermoplastic polymer B (hereinafter, also simply referred to as “polymer B”) used in the present invention is a thermoplastic polymer other than the thermoplastic polyurethane elastomer described above, and forms a mixed fiber together with the polymer A, and consists of this mixed fiber. If it can manufacture a nonwoven fabric, it will not specifically limit. Among such thermoplastic polymers B, polymers that can form fibers that are inferior in elasticity to fibers made of polymer A are preferred, and polymers that can form non-stretchable fibers having extensibility are more preferred. In particular, a stretchable nonwoven fabric produced using a polymer capable of forming a stretchable non-stretchable fiber exhibits a bulky feeling due to stretching, improves the tactile sensation, and may impart a stretch stop function to the stretchable nonwoven fabric. it can.

  Examples of the thermoplastic polymer B include styrene elastomers, polyolefin elastomers, vinyl chloride elastomers, polyesters, ester elastomers, polyamides, amide elastomers, polyolefins such as polyethylene, polypropylene, and polystyrene, and polylactic acid. . These may be used alone or in combination of two or more. When two or more thermoplastic polymers are used in combination, these polymers may be blended and spun, or spun to form a composite fiber.

  Specific examples of the various thermoplastic polymers described above are the same as the other thermoplastic polymers of the polymer A.

  Among these thermoplastic polymers, in particular, when forming a stretchable nonwoven fabric used for sanitary materials such as disposable diapers, it is possible to obtain a good feel and have excellent heat sealability with other disposable diaper members. From the viewpoint of being obtained, polyolefins, particularly polyethylene and polypropylene are preferably used as the thermoplastic polymer B.

<Mixed fiber and stretchable nonwoven fabric>
The mixed fiber and stretchable nonwoven fabric according to the present invention can be obtained by, for example, spunbond molding using the polymer A containing the thermoplastic polyurethane elastomer and the thermoplastic polymer B described above. A conventionally known method can be applied to the spunbond molding method used here, and examples thereof include a method described in JP-A-2002-242069.

  Specifically, first, the polymer A and the polymer B are melted by separate extruders or the like (step (I)). Next, these polymers are independently introduced into the same die, and the polymer A and the polymer B are simultaneously and independently discharged from different nozzles disposed on the die. Thereby, a fiber A made of polymer A and a fiber B made of polymer B are formed. The die temperature is usually 180 to 240 ° C, preferably 190 to 230 ° C, more preferably 200 to 225 ° C. A large number of fibers thus melt-spun are introduced into a cooling chamber, cooled with cooling air, and then stretched with stretched air to deposit the mixed fibers according to the present invention on the moving collection surface (step (II )). The cooling air temperature is usually 5 to 50 ° C., preferably 10 to 40 ° C., more preferably 15 to 30 ° C. from the viewpoints of economy and spinnability. The wind speed of the stretched air is usually 100 to 10,000 m / min, preferably 500 to 10,000 m / min.

  By the above method, a mixed fiber including the fiber A made of the polymer A and the fiber B made of the polymer B can be obtained. Here, when an elastomer is contained in the polymer B, the fiber B exhibits stretchability. On the other hand, when a polymer not containing an elastomer is used as the thermoplastic polymer B, the fiber B becomes non-stretchable.

  The fiber diameter of the mixed fiber is usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. The mixed fiber contains the fiber A in an amount of usually 10% by weight or more, preferably 20% by weight or more, and more preferably 40% by weight or more.

After the mixed fibers are deposited in a web shape on the moving collection surface by the above method, the deposit is subjected to a confounding process using a needle punch, a water jet, an ultrasonic seal or the like, or a heat fusion process using a hot embossing roll. The deposit is partially fused (step (III)). At this time, heat fusion treatment with a hot embossing roll is preferably used. The embossing temperature is usually 50 to 160 ° C, preferably 70 to 150 ° C. Although the embossing area ratio of an embossing roll can be determined suitably, Preferably it is 5 to 30%.

  The stretchable nonwoven fabric according to the present invention can be obtained by drawing the mixed fibers partially fused as described above (step (IV)). By performing the stretching process, it is possible to obtain a nonwoven fabric that is further excellent in touch and stretchability. The stretching method can be a conventionally known method, and may be a partially stretching method or a generally stretching method. Moreover, it may be uniaxially stretched or biaxially stretched. As a method of drawing in the machine flow direction (MD), for example, mixed fibers partially fused to two or more nip rolls are passed. At this time, the mixed fiber partially fused can be drawn by increasing the rotational speed of the nip roll in the order of the machine flow direction. Further, gear stretching can be performed using the gear stretching apparatus shown in FIG.

  The draw ratio is preferably 50% or more, more preferably 100% or more, most preferably 200% or more, and preferably 1000% or less, more preferably 400% or less. The preferred stretch ratio is either the machine flow direction (MD) stretch ratio in the case of uniaxial stretching or the direction perpendicular to the machine direction (CD), and in the case of biaxial stretching, the machine flow direction ( MD) and the direction perpendicular to this (CD). By drawing at such a draw ratio, the fiber diameter of the nonwoven fabric is usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less.

  The nonwoven fabric obtained in this way is excellent in fluff resistance, suitable for sanitary materials such as disposable diapers, sanitary napkins, urine pads, etc., and has good touch and elasticity. In particular, the above effects can be further improved by drawing a mixed fiber containing a fiber A made of a polymer containing TPU and a fiber B having an extensibility made of a polymer containing polyethylene and / or polypropylene at the draw ratio described above. The nonwoven fabric which has is obtained.

  The stretchable nonwoven fabric according to the present invention is excellent in heat sealability. For this reason, when a laminated body is formed using this nonwoven fabric and another nonwoven fabric, the layer which consists of this nonwoven fabric shows the outstanding adhesiveness, and is hard to peel. In particular, when a non-woven fabric having extensibility is used as another non-woven fabric, the obtained laminate has a further excellent tactile sensation.

  The elastic nonwoven fabric has a residual strain after 100% elongation of usually 50% or less, preferably 35% or less, more preferably 30% or less. By setting the residual strain to 50% or less, when the stretchable nonwoven fabric is used for clothing, sanitary materials, and sports materials, it is possible to make the shape of the product inconspicuous.

The basis weight of the stretchable nonwoven fabric is usually 3 to 200 g / m ² , preferably 5 to 150 g / m ² .

[Laminate]
The laminate according to the present invention is a laminate containing at least one layer composed of the stretchable nonwoven fabric. This laminate can be manufactured by the following method. After the mixed fibers are deposited in the same manner as described above, for example, a stretchable nonwoven fabric is laminated on the deposit. These are then fused and further stretched. Examples of the fusion method include entanglement treatment and heat fusion treatment similar to those described above, and heat embossing is preferably used. The embossing area ratio and stretching ratio of the embossing roll are preferably in the same range as described above. As the stretching method, the same method as in the case of stretching a stretchable nonwoven fabric can be applied.

  The nonwoven fabric having extensibility is not particularly limited as long as it can follow the maximum elongation of the stretchable nonwoven fabric. However, when the laminate is used as a sanitary material such as a disposable diaper, a good touch feeling, high Since stretchability and excellent heat sealability are required, a nonwoven fabric made of a polymer containing polyolefins, particularly polyethylene and / or polypropylene is preferably used. When the laminate is formed by applying heat embossing, the stretchable nonwoven fabric is preferably a nonwoven fabric made of a polymer exhibiting good compatibility and adhesion with the stretchable nonwoven fabric according to the present invention.

  The fibers forming the stretchable nonwoven fabric are preferably monocomponent, core-sheath, split, sea-island, and side-by-side fibers, and may be mixed fibers thereof.

  Moreover, what laminated | stacked the thermoplastic polymer film on the layer which consists of the said elastic nonwoven fabric as a laminated body which concerns on this invention is mentioned. This thermoplastic polymer film may be a breathable film or an apertured film.

  In the laminate thus obtained, the nonwoven fabric layer composed of the mixed fibers has excellent heat-sealability, so that peeling between layers does not occur. Moreover, it is an elastic laminate having an extremely good tactile sensation.

[Example]
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited at all by this Example. Analysis and evaluation of TPU in Examples and Comparative Examples were performed according to the following methods.

(1) Solidification start temperature It measured with the differential scanning calorimeter (DSC220C) connected to the SSC5200H disk station by Seiko Denshi Kogyo Co., Ltd. As a sample, about 8 mg of ground TPU was collected in an aluminum pan, covered with a cover and crimped. Similarly, alumina was collected as a reference. After setting the sample and the reference at a predetermined position in the cell, the measurement was performed in a nitrogen stream at a flow rate of 40 Nml / min. The temperature was raised from room temperature to 230 ° C. at a temperature raising rate of 10 ° C./min, held at this temperature for 5 minutes, and then lowered to −75 ° C. at a temperature lowering rate of 10 ° C./min. The starting temperature of the exothermic peak derived from the solidification of TPU recorded at this time was measured and used as the solidification starting temperature (unit: ° C.).

(2) Number of particles insoluble in polar solvent Measurement was carried out using a multi-cerser II manufactured by Beckman Coulter as a particle size distribution measuring device based on the pore electrical resistance method. In a 5 liter separable flask, 3500 g of dimethylacetamide (special grade manufactured by Wako Pure Chemical Industries, Ltd.) and 145.83 g of ammonium thiocyanate (special grade manufactured by Junsei Chemical Co., Ltd.) are weighed and allowed to stand at room temperature for 24 hours. And dissolved. Subsequently, it filtered under reduced pressure with a 1 micrometer membrane filter, and the reagent A was obtained. 180 g of reagent A and 2.37 g of TPU pellets were precisely weighed in a 200 cc glass bottle, and the soluble content in TPU was dissolved over 3 hours, which was used as a measurement sample. A 100 μm aperture tube was attached to Multisizer II, the solvent in the apparatus was replaced with reagent A, and the degree of vacuum was adjusted to about 3000 mmAq. 120 g of reagent A was weighed into a well-washed sample beaker, and it was confirmed that the amount of pulses generated by blank measurement was 50 or less. After setting the optimal Current value and Gain manually, calibration was performed using 10 μm uncrosslinked polystyrene standard particles. The measurement was performed for 210 seconds by weighing 120 g of reagent A and about 10 g of the measurement sample in a well-washed sample beaker. A value obtained by dividing the number of particles counted by this measurement by the weight of TPU sucked into the aperture tube was defined as the number of particles insoluble in the polar solvent (unit: number / g). The TPU weight was calculated by the following formula.

TPU weight = {(A / 100) × B / (B + C)} × D
In the formula, A: TPU concentration (% by weight) of measurement sample, B: Weight of measurement sample weighed in beaker (g), C: Weight of reagent A weighed in beaker (g), D: In measurement ( The amount of solution (g) sucked into the aperture tube during 210 seconds).

(3) Ratio of heat of fusion of hard domain Measured with a differential scanning calorimeter (DSC220C) connected to an SSC5200H disk station manufactured by Seiko Instruments Inc. As a sample, about 8 mg of ground TPU was collected in an aluminum pan, covered with a cover and crimped. Similarly, alumina was collected as a reference. After setting the sample and the reference at a predetermined position in the cell, the measurement was performed in a nitrogen stream at a flow rate of 40 Nml / min. The temperature was increased from room temperature to 230 ° C. at a rate of temperature increase of 10 ° C./min. At this time, it is calculated | required from the sum total (a) of the heat of fusion calculated | required from the endothermic peak in the range whose peak temperature is 90 degreeC or more and 140 degrees C or less, and the endothermic peak in which the peak temperature exceeds 140 degreeC and is 220 degrees C or less. The total amount of heat of fusion (b) was determined, and the ratio of heat of fusion of hard domains (unit:%) was determined by the following equation.

Hard domain melting heat ratio (%) = a / (a + b) × 100
(4) Melt viscosity at 200 ° C. (hereinafter simply referred to as “melt viscosity”)
Using a capillograph (Model 1C manufactured by Toyo Seiki Co., Ltd.), the melt viscosity (unit: unit: Pa · s) of TPU at a shear rate of 100 sec ⁻¹ at 200 ° C. was measured. A nozzle having a length of 30 mm and a diameter of 1 mm was used.

(5) Moisture value of TPU The moisture content (unit: ppm) of TPU is measured by combining the moisture content measuring device (AVQ-5S manufactured by Hiranuma Sangyo Co., Ltd.) and the water vaporizer (EV-6 manufactured by Hiranuma Sangyo Co., Ltd.). It was. About 2 g of TPU pellets weighed in a heated sample pan were put into a heating furnace at 250 ° C., and the evaporated water was introduced into a titration cell of a moisture measuring device from which residual moisture had been removed in advance and titrated with a Karl Fischer reagent. The titration was completed when no change in the potential of the titration electrode accompanying the change in the amount of water in the cell occurred for 20 seconds.

(6) Shore A hardness TPU hardness was measured by the method described in JIS K-7311 at 23 ° C. and 50% relative humidity. The durometer was type A.

(7) Number of yarn breaks The state of spinning in the vicinity of the nozzle surface was visually observed, and the number of yarn breaks per 5 minutes (unit: times / 5 min) was counted. Here, “thread breakage” is defined as the phenomenon that one fiber breaks independently during molding as one thread breakage, and when the fibers are fused to break the fibers, they are not included as fiber fusion. Shall.

(8) Number of fusions The spinning state in the vicinity of the nozzle surface was visually observed, and the number of fiber fusions per 5 minutes (unit: times / 5 min) was counted.

<TPU production example 1>
280.3 parts by weight of 4,4′-diphenylmethane diisocyanate (Mitsui Takeda Chemical Co., Ltd., trade name: Cosmonate PH, hereinafter referred to as “MDI”) in an isocyanate compound storage tank (hereinafter referred to as tank A), The mixture was charged in a nitrogen atmosphere and adjusted to 45 ° C. with stirring to such an extent that bubbles were not mixed.

  219.8 parts by weight of a polyester polyol having a number average molecular weight of 1000 (Mitsui Takeda Chemical Co., Ltd., trade name: Takelac U2410) and a polyester polyol having a number average molecular weight of 2000 (Mitsui Takeda Chemical Co., Ltd., trade name: Takelac U2420) ) 439.7 parts by weight, bis (2,6-diisopropylphenyl) carbodiimide (manufactured by Raschig GmbH, trade name: Stabilizer 7000) 2.97 parts by weight, hindered phenolic antioxidant (Ciba Specialty Chemicals) A polyol storage tank (hereinafter referred to as "Product Name: Irganox 1010", 2.22 parts by weight) and 2.22 parts by weight of a benzotriazole ultraviolet absorber (manufactured by Johoku Chemical Co., Ltd., trade name: JF-83). Tank B) is charged in a nitrogen atmosphere and stirred. It was adjusted in La 90 ℃. This mixture is referred to as polyol solution 1.

  60.2 parts by weight of a chain extender 1,4-butanediol (manufactured by BASF Japan Ltd.) was charged into a chain extender storage tank (hereinafter referred to as tank C) under a nitrogen atmosphere and adjusted to 50 ° C. .

  The hard segment amount calculated from these reaction raw materials is 34% by weight.

  Next, a high-speed stirrer adjusted to 120 ° C. with a flow rate of 16.69 kg / h of MDI and a flow rate of 39.72 kg / h of polyol solution 1 at a liquid feed line via a gear pump and a flow meter ((stock) The solution was quantitatively passed through Sakai Plant, Model: SM40), stirred and mixed at 2000 rpm for 2 minutes, and then sent to a reaction pot equipped with a stirrer adjusted to 120 ° C. Further, this mixed solution was quantitatively transferred from a reaction pot to a high-speed stirrer (SM40) adjusted to 120 ° C. at a flow rate of 56.41 kg / h and 1,4-butanediol from a tank C at a flow rate of 3.59 kg / h. The mixture was passed through and stirred and mixed at 2000 rpm for 2 minutes. Thereafter, this mixed solution was passed through a static mixer whose inside was coated with Teflon (registered trademark) or protected with a Teflon (registered trademark) tube. The static mixer unit was connected to the first to third static mixers (temperature 250 ° C.) in which three static mixers having a pipe length of 0.5 m and an inner diameter of 20 mmφ were connected, and three static mixers having a pipe length of 0.5 m and an inner diameter of 20 mmφ. Fourth to sixth static mixers (temperature 220 ° C.), pipe length 1.0 m, seventh to twelfth static mixers (temperature 210 ° C.) connected with six static mixers having an inner diameter of 34 mmφ, pipe length 0.5 m, A thirteenth to fifteenth static mixer (temperature 200 ° C.) connected with three static mixers having an inner diameter of 38 mmφ is connected in series.

  The reaction product flowing out from the 15th static mixer was passed through a gear pump and a single screw extruder (diameter 65 mmφ, temperature 200 to 215) attached with a polymer filter (manufactured by Nagase Sangyo Co., Ltd., trade name: Dena filter) at the tip. And extruded from a strand die. After cooling with water, it was continuously pelletized with a pelletizer. Next, the obtained pellets were charged into a dryer and dried at 85 to 90 ° C. for 8 hours to obtain a thermoplastic polyurethane elastomer (TPU-1) having a moisture value of 65 ppm.

  The solidification start temperature of TPU-1 is 115.6 ° C., the number of particles insoluble in the polar solvent is 1.4 million particles / g, the hardness of the test piece prepared by injection molding is 86 A, the melt viscosity at 200 ° C. is 2100 Pa · s, hard The heat of fusion ratio of the domain was 62.8%.

<TPU production example 2>
288.66 parts by weight of MDI was charged into tank A under a nitrogen atmosphere and adjusted to 45 ° C. with stirring to such an extent that bubbles were not mixed.

  216.2 parts by weight of polytetramethylene ether glycol having a number average molecular weight of 1000 (manufactured by Hodogaya Chemical Co., Ltd., trade name: PTG-1000) and polyester polyol having a number average molecular weight of 2000 (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name) : Takelac U2720) 432.5 parts by weight, Irganox 1010 2.22 parts by weight, and JF-83 2.22 parts by weight were charged in tank B under a nitrogen atmosphere and adjusted to 95 ° C. with stirring. . This mixture is referred to as polyol solution 2.

  In a nitrogen atmosphere, 62.7 parts by weight of 1,4-butanediol as a chain extender was charged into tank C and adjusted to 50 ° C.

  The hard segment amount calculated from these reaction raw materials is 35% by weight.

  Next, a high-speed stirrer (SM40) adjusted to 120 ° C. with a flow rate of 17.24 kg / h for MDI and a flow rate of 39.01 kg / h for polyol solution 2 in a liquid feed line via a gear pump and a flow meter. The solution was quantitatively passed through and stirred and mixed at 2000 rpm for 2 minutes, and then sent to a reaction pot equipped with a stirrer adjusted to 120 ° C. Further, this mixed solution was quantitatively transferred from a reaction pot to a high-speed stirrer (SM40) adjusted to 120 ° C. at a flow rate of 56.25 kg / h and 1,4-butanediol from a tank C at a flow rate of 3.74 kg / h. The mixture was passed through and stirred and mixed at 2000 rpm for 2 minutes. Thereafter, this mixed solution was passed through the same static mixer as in Production Example 1 above.

  The reaction product flowing out from the fifteenth static mixer was pelletized in the same manner as in Production Example 1. The obtained pellets were charged into a dryer and dried at 85 to 90 ° C. for 8 hours to obtain a thermoplastic polyurethane elastomer (TPU-2) having a moisture value of 70 ppm.

  The solidification start temperature of TPU-2 is 106.8 ° C., the number of particles insoluble in the polar solvent is 1.5 million particles / g, the hardness by a test piece prepared by injection molding is 85 A, the melt viscosity at 200 ° C. is 1350 Pa · s, hard The heat of fusion ratio of the domain was 55.1%.

<TPU production example 3>
MDI was charged into tank A under a nitrogen atmosphere and adjusted to 45 ° C. with stirring to such an extent that bubbles were not mixed.

  628.6 parts by weight of a polyester polyol having a number average molecular weight of 2000 (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name: Takelac U2024), 2.21 parts by weight of Irganox 1010, and 77.5 weights of 1,4-butanediol Were charged in tank B under a nitrogen atmosphere and adjusted to 95 ° C. with stirring. This mixture is referred to as polyol solution 3.

  The hard segment amount calculated from these reaction raw materials is 37.1% by weight.

Next, a high-speed stirrer (SM40) adjusted to 120 ° C. with a flow rate of 17.6 kg / h for MDI and a flow rate of 42.4 kg / h for polyol solution 3 in a liquid feed line via a gear pump and a flow meter. Then, the mixture was stirred and mixed at 2000 rpm for 2 minutes, and then passed through a static mixer in the same manner as in Production Example 1. The static mixer unit was connected to the first to third static mixers (temperature 230 ° C.) in which three static mixers having a pipe length of 0.5 m and an inner diameter of 20 mmφ were connected, and three static mixers having a pipe length of 0.5 m and an inner diameter of 20 mmφ. Fourth to sixth static mixers (temperature 220 ° C.), pipe length 1.0 m, inner diameter 34
Seventh to twelfth static mixers (temperature 210 ° C.) connected with six mmφ static mixers, and thirteenth to fifteenth static mixers (temperature 200) connected with three static mixers with a pipe length of 0.5 m and an inner diameter of 38 mmφ. ° C) in series.

  The reaction product flowing out from the fifteenth static mixer was passed through a gear pump and a single screw extruder (diameter 65 mmφ, temperature 180 to 210) attached with a polymer filter (manufactured by Nagase Sangyo Co., Ltd., trade name: Dena filter) at the tip. And extruded from a strand die. After cooling with water, it was continuously pelletized with a pelletizer. Next, the obtained pellets were charged into a dryer and dried at 100 ° C. for 8 hours to obtain a thermoplastic polyurethane elastomer having a moisture value of 40 ppm. This thermoplastic polyurethane elastomer was continuously extruded with a single-screw extruder (diameter 50 mmφ, temperature 180 to 210 ° C.) and pelletized. It was again dried at 100 ° C. for 7 hours to obtain a thermoplastic polyurethane elastomer (TPU-4) having a moisture value of 57 ppm.

  The solidification start temperature of TPU-4 is 103.7 ° C., the number of particles insoluble in the polar solvent is 1.5 million particles / g, the hardness by a test piece prepared by injection molding is 86 A, the melt viscosity at 200 ° C. is 1900 Pa · s, hard The heat of fusion ratio of the domain was 35.2%.

(1) Preparation of spunbonded nonwoven fabric MFR (based on ASTM D1238, measured at a temperature of 230 ° C. and a load of 2.16 kg) 60 g / 10 min, a density of 0.91 g / cm ³ and a melting point of 160 ° C. 96 parts by weight (abbreviated as “PP-1”) and MFR (measured at a temperature of 190 ° C. and a load of 2.16 kg in accordance with ASTM D1238) 5 g / 10 min, density 0.97 g / cm ³ , melting point 134
A thermoplastic polymer B-1 was prepared by mixing 4 parts by weight of high-density polyethylene (hereinafter abbreviated as “HDPE”) at 0 ° C.

After melting TPU-1 and thermoplastic polymer B-1 prepared in Production Example 1 independently using an extruder (30 mmφ), a spunbond molding machine (collecting surface) having a spinneret shown in FIG. a length in a direction perpendicular to the flow direction of the upper of the machine: 100 mm) using, 220 ° C. resin temperature and the die temperature is together, cooling air temperature 20 ° C., the spun bond method in the conditions of stretching air wind 3000 m / min The melt spinning was performed, and a web made of mixed fibers containing fibers A made of TPU-1 and fibers B made of thermoplastic polymer B-1 was deposited on the collecting surface. The spinneret has a nozzle arrangement pattern as shown in FIG. 2, has a nozzle diameter of 0.6 mmφ, the nozzle pitch is 8 mm in the vertical direction and 8 mm in the horizontal direction, and the ratio of the number of nozzles is the nozzle for fiber A: The nozzle for fiber B = 1: 3. The single hole discharge rate of the fiber A was 1.0 g / (minute / hole), and the single hole discharge amount of the fiber B was 0.45 g / (minute / hole).

The web former speed was 20 m / min, and the resulting web was embossed at 80 ° C. (embossed area ratio: 7%, embossed roll diameter: 150 mmφ, stamping pitch: 2.1 mm in the vertical and horizontal directions, stamped shape: rhombus ) To produce a spunbonded nonwoven fabric having a basis weight of 100 g / m ² .

(2) Evaluation of tactile sensation of nonwoven fabric before stretching treatment The tactile sensation of the spunbonded nonwoven fabric prepared as described above was evaluated. Ten panelists confirmed the touch of the nonwoven fabric and evaluated it according to the following criteria.
A: When 10 out of 10 people feel that there is no stickiness and feel is good.
B: 9 to 7 out of 10 people feel that there is no stickiness and feel is good.
C: When 6 to 3 out of 10 people feel that there is no stickiness and feel is good.
D: When 2 to 0 out of 10 people feel that there is no stickiness and feel is good.

(3) Stretching treatment From the spunbond nonwoven fabric obtained in the above (1), 5 nonwoven fabrics having a flow direction (MD) of 5.0 cm and a transverse direction (CD) of 2.5 cm were cut out. The nonwoven fabric was stretched under conditions of 30 mm between chucks, a tensile speed of 30 mm / min, and a stretching ratio of 100%, and then immediately recovered to the original length at the same speed to obtain a stretchable nonwoven fabric. At that time, when the tensile load reached 0 gf, the strain was measured, and the average value of the five nonwoven fabrics was evaluated as the residual strain (unit:%).

(4) Evaluation of stretchable nonwoven fabric The tactile sensation of the stretchable nonwoven fabric obtained in the above (3) was evaluated based on the same criteria as in the above (2).

  Further, after measuring the strain by the stretching process of (3) above, the film was continuously stretched again by 100% under the same conditions as in (3) above, and the load at this time was measured. This measurement was performed on five stretchable nonwoven fabrics, and a value obtained by dividing the average value by the basis weight was defined as tensile strength (unit: gf / weight per unit).

(5) Measurement of average minimum fiber diameter Discharge of thermoplastic polymer B-1 is stopped, and only TPU-1 is used, melt spinning is performed in the same manner as in (1) above, and the stretched air wind speed is increased until yarn breakage occurs. The drawing air wind speed was increased by 250 m / min, and the drawing air wind speed that was 250 m / min slower than the drawing air wind speed when yarn breakage occurred was determined. The web was formed by melt spinning in the same manner as (1) above using only TPU-1 at the stretched air wind speed thus determined, and depositing the fibers. This web is defined as the web in the minimum fiber state. The web in the minimum fiber state was photographed at a magnification of 200 times, and the image was analyzed with image dimension measurement software (Pixs2000 Version 2.0 manufactured by Innotech). The diameter was measured for 100 fibers, and the average minimum fiber diameter (unit: μm) of the fibers composed of TPU-1 was determined.

  These evaluation results are shown in Table 1.

  A stretchable nonwoven fabric was produced in the same manner as in Example 1 except that TPU-2 was used instead of TPU-1. Table 1 shows the results of evaluating the obtained nonwoven fabric in the same manner as in Example 1.

  Moreover, the average minimum fiber diameter of the fiber which consists of TPU-2 was calculated | required like Example 1 except having used TPU-2 instead of TPU-1. The results are shown in Table 1.

TPU-4 is used in place of TPU-1, MFR (measured at a temperature of 190 ° C. and a load of 2.16 kg in accordance with ASTM D1238) 30 g / 10 minutes, density 0.95 g instead of thermoplastic polymer B-1. / cm ^3, medium density polyethylene having a melting point of 125 ° C. (hereinafter, "MDPE
A stretchable nonwoven fabric was produced in the same manner as in Example 1, except that “abbreviated”) was used. Table 1 shows the results of evaluating the obtained nonwoven fabric in the same manner as in Example 1.

  Moreover, the average minimum fiber diameter of the fiber which consists of TPU-4 was calculated | required like Example 1 except having used TPU-4 instead of TPU-1. The results are shown in Table 1.

[Comparative Example 1]
A thermoplastic polyurethane elastomer (made by BASF Japan Ltd., trade name: Elastollan 1180A-10) having a solidification start temperature of 78.4 ° C., a polar solvent-insoluble particle number of 3.2 million particles / g, and a hardness of 82A, It was previously dried at 100 ° C. for 8 hours using a dryer, and the moisture value was 115 ppm.

  This 1180A-10 is used as a core, linear low density polyethylene (exxon, trade name: Exact3017, hereinafter abbreviated as “LLDPE”) is used as a sheath, and the core to sheath weight ratio is 85/15. The core-sheath type composite melt spinning was performed, and a web was prepared by a spunbond molding apparatus (length in the direction perpendicular to the machine flow direction on the collecting surface: 100 mm). The die temperature was 220 ° C., and the discharge amount per hole was 1.0 g / min.

The web deposited on the belt is embossed at 80 ° C. (embossed area ratio: 7%, embossed roll diameter: 150 mmφ, imprint pitch: 2.1 mm in the vertical and horizontal directions, imprinted shape: rhombus), and the basis weight is 100 g / m ^An attempt was made to produce ^two spunbond nonwovens.

  However, when spinning to a fiber diameter of 50 μm or less, many yarn breaks occurred in the spinning tower, so that the nonwoven fabric was not obtained and the nonwoven fabric could not be evaluated. The other evaluation results are shown in Table 1.

  Further, the average minimum fiber diameter of the concentric core-sheath composite fiber was determined in the same manner as in Example 1 except that the concentric core-sheath composite fiber was formed instead of the fiber composed of TPU-1. . The results are shown in Table 1.

[Comparative Example 2]
Span was applied in the same manner as in Comparative Example 1 except that TPU-1 was used for the core instead of 1180A-10, PP-1 was used for the sheath instead of LLDPE, and the weight ratio of the core to the sheath was changed to 50/50. A bonded nonwoven fabric was produced. The tactile sensation of this spunbonded nonwoven fabric was evaluated in the same manner as in Example 1.

  Next, this spunbonded nonwoven fabric was stretched in the same manner as in Example 1 to obtain a stretchable nonwoven fabric. Table 1 shows the results of evaluating the obtained stretchable nonwoven fabric in the same manner as in Example 1. This nonwoven fabric had a large residual strain and low stretch characteristics.

  Also, the same as Comparative Example 1 except that TPU-1 was used for the core instead of 1180A-10, PP-1 was used for the sheath instead of LLDPE, and the weight ratio of the core to the sheath was changed to 50/50. The average minimum fiber diameter of the concentric core-sheath type composite fiber was determined. The results are shown in Table 1.

[Comparative Example 3]
Comparative Example 2 except that TPU-1 and PP-1 were used at a weight ratio of 50/50, and composite melt spinning was performed by a hollow 8-split nozzle instead of concentric core-sheath composite melt spinning In the same manner, an elastic nonwoven fabric was obtained.

  Table 1 shows the results of evaluating the obtained nonwoven fabric in the same manner as in Example 1. This nonwoven fabric had a large residual strain and low stretch characteristics.

  Further, except that TPU-1 and PP-1 were used at a weight ratio of 50/50, and composite melt spinning was performed using a hollow 8-split nozzle instead of a concentric core-sheath composite melt spinning. In the same manner as in Example 2, the average minimum fiber diameter of the 8-divided composite fiber was determined. The results are shown in Table 1.

[Comparative Example 4]
Thermosetting polyurethane elastomer with a solidification start temperature of 60.2 ° C., a polar solvent insoluble content of 1.4 million particles / g, and a hardness of 75 A (trade name: Elastollan XET-275-10MS, manufactured by BASF Japan Ltd.) Was previously dried at 100 ° C. for 8 hours using a dryer, and the moisture value was 89 ppm.

  A stretchable nonwoven fabric composed of mixed fibers was produced in the same manner as in Example 1 except that this XET-275-10MS was used instead of TPU-1. In this production, the fiber was fused to the spinning tower and the spinnability was poor.

  Table 1 shows the results of evaluating the obtained nonwoven fabric in the same manner as in Example 1. This nonwoven fabric was inferior in touch.

  Moreover, the average minimum fiber diameter of the fiber which consists of XET-275-10MS was calculated | required like Example 1 except having used this XET-275-10MS instead of TPU-1. The results are shown in Table 1.

(1) Preparation of spunbond nonwoven fabric TPU-4 is used instead of TPU-1, an extruder (50 mmφ) is used instead of an extruder (30 mmφ), and a spunbond molding machine (machine flow direction on the collecting surface) In the same manner as in Example 1 except that a spunbond molding machine (length in the direction perpendicular to the machine flow direction on the collecting surface: 800 mm) was used instead of A web made of mixed fibers containing fibers A made of TPU-4 and fibers B made of thermoplastic polymer B-1 was deposited on the collecting surface.

Except for changing the embossing temperature to 120 ° C, the embossing area ratio to 18%, the embossing roll diameter to 400 mmφ, and the basis weight to 70 g / m ² , the web is embossed in the same manner as in Example 1 to produce a spunbond nonwoven fabric. did.

(2) Stretching treatment From the spunbond nonwoven fabric obtained in the above (1), 5 nonwoven fabrics having a flow direction (MD) of 15.0 cm and a transverse direction (CD) of 5.0 cm were cut. This nonwoven fabric was stretched under conditions of 100 mm between chucks, a tensile speed of 100 mm / min, and a stretching ratio of 200%, and then immediately recovered to the original length at the same speed to obtain a stretchable nonwoven fabric.

(3) Evaluation of stretchable nonwoven fabric The tactile sensation of the stretchable nonwoven fabric obtained in the above (2) was evaluated on the same basis as in Example 1.

  In addition, after the stretching process (2), the chuck is opened to remove the deflection caused by the residual strain generated by the stretching process, and the stretching is performed again under the conditions of 100 mm between chucks, a pulling speed of 100 mm / min, and a stretching ratio of 100%. The load at this time was measured. After that, it was immediately recovered to the original length at the same speed. At this time, the strain when the tensile load reached 0 gf was measured. The average value of the load at the time of 100% elongation for the five stretchable nonwoven fabrics was obtained, and the value obtained by dividing this by the basis weight was taken as the tensile strength (unit: gf / weight per unit). The average value of strain was evaluated as residual strain (unit:%).

(4) Measurement of average minimum fiber diameter In the same manner as in Example 1, the average minimum fiber diameter of fibers composed of TPU-4 was determined.

  These evaluation results are shown in Table 2.

A stretchable nonwoven fabric was produced in the same manner as in Example 4 except that the basis weight was changed to 137 g / m ² . Table 2 shows the results of evaluating the obtained nonwoven fabric in the same manner as in Example 4.

  Moreover, the average minimum fiber diameter of the fiber consisting of TPU-4 was determined in the same manner as in Example 4.

The single hole discharge rate of fiber B is changed to 0.90 g / (minute / hole), the mixing ratio (A / B) of fiber A and fiber B is changed to 27/73, and the basis weight is changed to 104 g / m ² . A stretchable nonwoven fabric was produced in the same manner as in Example 4 except that. Table 2 shows the results of evaluating the obtained nonwoven fabric in the same manner as in Example 4.

  Moreover, the average minimum fiber diameter of the fiber consisting of TPU-4 was determined in the same manner as in Example 4.

Using the same molding machine as in Example 4 except that TPU-4 was used instead of TPU-1, the basis weight was changed to 60 g / m ² and the draw ratio was changed to 150%, the flow direction (MD ) A stretchable nonwoven fabric having a size of 5.0 cm and a transverse direction (CD) of 2.5 cm was produced.

  This stretchable nonwoven fabric was stretched 50% at a chuck interval of 30 mm and a tensile speed of 30 mm / min, and held at 40 ° C. for 120 minutes in a stretch ratio of 50%.

  The stress retention rate of this stretchable nonwoven fabric was 56.5% under conditions of a draw ratio of 50% and a retention time of 120 minutes.

[Comparative Example 5]
A stretchable nonwoven fabric was produced in the same manner as in Example 7 except that SEBS (styrene / (ethylene-butylene) / styrene block copolymer) was used instead of TPU-4. The stress retention rate was 32.7% under the conditions of a draw ratio of 50% and a retention time of 120 minutes.

(1) Preparation of Non-woven Fabric Laminate Similar to Example 1, mixed fiber containing fiber A made of TPU-1 and fiber B made of thermoplastic polymer B-1 was deposited on the collecting surface to prepare a web. did. Next, a propylene homopolymer (hereinafter referred to as “PP-2”) having an MFR (according to ASTM D1238, measured at a temperature of 230 ° C. and a load of 2.16 kg) of 15 g / 10 minutes, a density of 0.91 g / cm ³ and a melting point of 160 ° C.
”) Is used for the core, PP-1 is used for the sheath, and a core-sheath type composite melt spinning with a core-to-sheath weight ratio of 10/90 is performed by the spunbond method, and the mixed fiber is used. Deposited on the web.

The two-layered deposit was embossed at 120 ° C. (embossed area ratio: 7%, embossed roll diameter: 150 mmφ, imprint pitch: longitudinal and transverse directions 2.1 mm, imprinted shape: rhombus), and the basis weight was 140 g / An m ² spunbond nonwoven fabric laminate was produced.

(2) Evaluation of tactile sensation of laminate before stretching treatment The tactile sensation of the nonwoven fabric laminate prepared as described above was evaluated based on the same criteria as in Example 1.

(3) Stretching treatment Five laminates having a flow direction (MD) of 5.0 cm and a transverse direction (CD) of 2.5 cm were cut from the nonwoven fabric laminate obtained in (1) above. The laminate was stretched under the conditions of 30 mm between chucks, a tensile speed of 30 mm / min, and a draw ratio of 100%, and then immediately recovered to the original length at the same speed to obtain a laminate having a stretchable nonwoven fabric. At that time, when the tensile load reached 0 gf, the strain was measured, and the average value of the five test pieces was evaluated as the residual strain (unit:%).

(4) Evaluation of laminated body The tactile sensation of the laminated body obtained in the above (3) was evaluated on the same basis as in Example 1.

  After measuring the strain by the stretching treatment of (3) above, it was stretched again 100% under the same conditions as it was, and the load at this time was measured. This measurement was performed on five laminates, and a value obtained by dividing the average value by the basis weight was defined as tensile strength (unit: gf / weight per unit).

  From the laminate obtained in (3) above, a test piece was cut into a strip having a width of 25 mm. A part of the test piece was peeled from the nonwoven fabric layer in the longitudinal direction, and the peeled ends were attached to a jig of a testing machine (MODEL2005 model manufactured by Isotesco) in a T shape so that the distance between chucks was 50 mm. (180 degree peeling). The nonwoven fabric layer was peeled at a peeling speed of 100 mm / min in an atmosphere of 23 ° C. and 50% relative humidity, and the adhesive strength (unit: g / 25 mm) between the nonwoven fabric layers was measured.

  These evaluation results are shown in Table 3.

[Comparative Example 6]
A laminate was produced in the same manner as in Example 8 except that single fiber was melt-spun using TPU-1 instead of the mixed fiber. Table 3 shows the results obtained by evaluating the obtained laminate in the same manner as in Example 8. This laminate had a weak interlaminar adhesive strength and was insufficient for use as an elastic member.

  The stretchable nonwoven fabric according to the present invention is excellent in productivity, tactile sensation, and heat sealability, has a small residual strain, and is highly elastic. Therefore, it can be used as sanitary materials, industrial materials, clothing, and sports materials.

FIG. 1 is a schematic view of a gear stretching apparatus. FIG. 2 is a conceptual diagram of a mixed fiber forming nozzle.

Explanation of symbols

A Nozzle for textile B B Nozzle for textile B

Claims (10)

Particles insoluble in dimethylacetamide measured by attaching a 100 μm aperture to a particle size distribution measuring device based on the pore electrical resistance method, having a solidification start temperature of 65 ° C. or higher measured by a differential scanning calorimeter (DSC) A mixed fiber containing a fiber A made of a polymer A containing a thermoplastic polyurethane elastomer having a number of 3 million pieces / g or less and a fiber B made of a thermoplastic polymer B other than the thermoplastic polyurethane elastomer was deposited in a web shape. A spunbonded nonwoven fabric obtained by partially fusing the deposit.   The spunbonded nonwoven fabric according to claim 1, wherein the fiber B is a non-stretchable fiber.   The spunbonded nonwoven fabric according to claim 1 or 2, wherein the polymer A contains 50% by weight or more of the thermoplastic polyurethane elastomer. The thermoplastic polyurethane elastomer is
The total amount of heat of fusion (a) obtained from an endothermic peak having a peak temperature in the range of 90 ° C. or higher and 140 ° C. or lower as measured by a differential scanning calorimeter (DSC), and the peak temperature exceeds 140 ° C. and is 220 ° C. or lower. The total amount of heat of fusion (b) obtained from the endothermic peak in the range of
a / (a + b) × 100 ≦ 80 (1)
The spunbonded nonwoven fabric according to any one of claims 1 to 3, wherein the relationship is satisfied. The spunbonded nonwoven fabric according to any one of claims 1 to 4 , wherein the thermoplastic polymer B is a polymer containing polyethylene and / or polypropylene. A stretchable spunbond nonwoven fabric obtained by stretching the spunbond nonwoven fabric according to any one of claims 1 to 5 . A laminate comprising at least one layer comprising the stretchable spunbonded nonwoven fabric according to claim 6 . A sanitary material comprising the stretchable spunbonded nonwoven fabric according to claim 6 . (I) A dimethylacetamide solvent insoluble measured by attaching a 100 μm aperture to a particle size distribution measuring apparatus based on the pore electrical resistance method having a solidification start temperature of 65 ° C. or higher measured by a differential scanning calorimeter (DSC) A step of independently melting the polymer A containing a thermoplastic polyurethane elastomer having a number of particles of 3 million particles / g or less and the thermoplastic polymer B other than the thermoplastic polyurethane elastomer,
(II) The polymer A and the polymer B are each independently extruded simultaneously from different nozzles arranged in the same die and spun to mix the fiber A made of the polymer A and the fiber B made of the polymer B Depositing fibers into a web;
(III) a step of partially fusing the deposit obtained in the previous step;
A method for producing a spunbond nonwoven fabric comprising: The steps (I) to (III) above, and
The method for producing a stretchable spunbonded nonwoven fabric according to claim 9 , comprising: (IV) a step of stretching the deposit partially fused in the previous step.

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