JP2004244790A - Stretch nonwoven fabric and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stretch nonwoven fabric obtained by subjecting a polymer containing a thermoplastic polyurethane elastomer to spunbond processing, having a good feeling to the touch, having high elasticity, and having small residual strain, and to provide a method for producing the same. <P>SOLUTION: This spunbonded stretch nonwoven fabric is composed of the fiber formed out of the polymer containing the thermoplastic polyurethane elastomer. The thermoplastic polyurethane elastomer has a solidification starting temperature of ≥ 65°C, when measured by a differential scanning calorimeter (DSC), and a particle number of ≤3,000,000 counts/g, when particles insoluble in a polar solvent are counted by attaching an aperture of a 100 μm size to a counter which detects electric resistance of the particles passing through the aperture and measures a particle size distribution of the particles. The fiber has a value of Sn/X<SB>ave</SB>of ≤0.15, wherein the value (Sn/X<SB>ave</SB>) is calculated by dividing a standard deviation of fiber diameters (Sn) by an average fiber diameter (X<SB>ave</SB>). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a stretchable nonwoven fabric obtained by spunbonding a polymer containing a thermoplastic polyurethane elastomer, a method for producing the same, and a sanitary material including the stretchable nonwoven fabric.

  A number of proposals have been made on stretchable nonwoven fabrics using a thermoplastic polyurethane elastomer (hereinafter sometimes abbreviated as “TPU”), including its high elastic properties, small residual strain, and excellent ventilation. Due to its properties, it is used for applications such as clothing, sanitary materials, and sports materials.

  As a typical method for producing a stretchable nonwoven fabric using TPU, there is a melt blown molding method. Stretchable nonwoven fabrics manufactured by this method are required to follow relatively human body movements such as disposable diaper sidebands, base cloth for emergency bandages, disposable gloves, etc. due to their high elasticity, flexibility and breathability. Used for

  On the other hand, Patent Document 1 discloses a nonwoven fabric which is a spunbonded nonwoven fabric, which is made of a thermoplastic elastomer and essentially consists of a web of continuous filaments. It is described that the spunbonded nonwoven fabric has a fiber diameter closer to the fiber diameter of the woven fabric, so that the suppleness and hand feel are close to those of the woven fabric, and have a better tactile sensation than the nonwoven fabric formed by melt blown molding. Although a thermoplastic polyurethane elastomer is also disclosed as a thermoplastic elastomer, the solidification starting temperature and the number of particles insoluble in a polar solvent are not disclosed. As shown in Comparative Examples 1 and 2 of the present specification, when the solidification start temperature is lower than 60 ° C. or the number of particles of the polar solvent-insoluble component exceeds 3,000,000 / g, yarn breakage or fusion between fibers occurs during spinning. However, there is a problem that the feel of the nonwoven fabric is deteriorated.

  Patent Document 2 discloses a thermoplastic polyurethane resin having a particle diameter in the range of 6 to 80 μm and having a number of particles of the polar solvent-insoluble component of 20,000 / g or less. Further, it is disclosed that this thermoplastic polyurethane resin is useful as a resin for polyurethane elastic fibers that can solve problems such as an increase in nozzle back pressure and yarn breakage during melt spinning. However, the present inventors tried additional tests of the examples described in Patent Document 2, but could not obtain the thermoplastic polyurethane resin.

  In Patent Document 3, as one of the problems when a nonwoven fabric is produced by a spunbond method using a thermoplastic elastomer, the property of "adhering easily" which is a characteristic of the thermoplastic elastomer is mentioned. It has been pointed out that turbulence in air may cause filaments to adhere to each other when forming a nonwoven fabric by a spunbond method. It is also stated that this "stickiness" is particularly troublesome when winding the web onto a roll. Another problem is that the strand breaks or is poor in elasticity during extrusion and / or stretching. The present inventors performed spunbond molding using TPU (Elastollan 1180A (manufactured by BASF Japan Ltd.)) described in Patent Document 3, but as shown in Comparative Example 2 of the present specification, Thread breakage occurred during spinning, and a satisfactory nonwoven fabric was not obtained.

Patent Document 4 discloses a stretchable nonwoven fabric using a thermoplastic polyurethane resin having a hardness (JIS-A hardness) of 65 to 98 degrees and a flow start temperature of 80 to 150 degrees Celsius. According to Patent Document 4, this nonwoven fabric forms a fiber by laminating continuous filaments of a thermoplastic polyurethane resin in a sheet shape, and then, at a contact point of the laminated filaments, fusion-bonds the filaments themselves with heat of its own to form fibers. Obtained by: This manufacturing method is a melt blown method. The present inventors manufactured a thermoplastic polyurethane resin by the method described in Patent Document 4, and manufactured a nonwoven fabric by spun bond molding using the thermoplastic polyurethane resin. However, as shown in Comparative Example 4 of the present specification, yarn breakage occurred during spinning, and a satisfactory nonwoven fabric was not obtained.

Patent Document 5 discloses a stretchable nonwoven fabric made of a composite fiber of crystalline polypropylene and a thermoplastic elastomer and having an excellent texture. Patent Document 5 discloses a stretchable nonwoven fabric (Example 6) composed of a concentric circular core-sheath composite fiber using 50% by weight of a urethane elastomer for a core and 50% by weight of a polypropylene for a sheath, and 50% by weight of a urethane elastomer. And a 50% by weight polypropylene and a stretchable non-woven fabric (Example 8) composed of a conjugate fiber having a fiber cross section of six divisions. These nonwoven fabrics are obtained by opening staple fibers with a carding machine and heat-treating with a through-air dryer. It is disclosed that the elongation recovery rate at 20% elongation is about 75%, and that it has an excellent texture. However, when used as clothing, sanitary materials, and sports materials, further improvement in stretch characteristics is required. I have.
Japanese Patent Publication No. Hei 7-503502 JP-A-9-87358 JP-T-2002-526553 WO99 / 39037 JP-A-9-291454

  The present invention is intended to solve the problems associated with the prior art as described above, and is obtained by spunbonding a polymer containing a thermoplastic polyurethane elastomer, and has a good tactile sensation, high elasticity, and small residual strain. It is an object to provide a stretchable nonwoven fabric and a method for producing the same.

  The present inventors have conducted intensive studies to solve the above problems, and by using a thermoplastic polyurethane elastomer having a specific range of a solidification start temperature and a polar solvent insoluble content, it is possible to narrow the fiber diameter distribution of the obtained nonwoven fabric. As a result, it was found that a nonwoven fabric having a good touch was obtained, and the present invention was completed.

That is, the stretchable nonwoven fabric according to the present invention is a stretchable nonwoven fabric formed of fibers formed from a polymer containing a thermoplastic polyurethane elastomer, and spunbonded,
The thermoplastic polyurethane elastomer has a solidification start temperature of at least 65 ° C. measured by a differential scanning calorimeter (DSC), and is measured by attaching a 100 μm aperture to a particle size distribution analyzer based on a pore electric resistance method. The number of particles of the polar solvent-insoluble component is 3,000,000 / g or less;
It said fibers, the value obtained by dividing the standard deviation of fiber diameter (Sn) by the average fiber diameter _{(X ave) (Sn / X} ave) is characterized in that more than 0.15.

  The polymer preferably contains the thermoplastic polyurethane elastomer in an amount of 10% by weight or more.

The thermoplastic polyurethane elastomer has a peak temperature of 140.degree. C., which is determined by a differential scanning calorimeter (DSC). The sum of the heats of fusion (b) determined from the endothermic peak in the range of over 220 ° C. to 220 ° C. is expressed by the following formula (1)
a / (a + b) × 100 ≦ 80 (1)
It is preferable that the sanitary material according to the present invention includes the elastic nonwoven fabric.

The method for producing a stretchable nonwoven fabric according to the present invention is a method for producing a stretchable nonwoven fabric comprising fibers formed from a polymer containing a thermoplastic polyurethane elastomer by spunbond molding,
The thermoplastic polyurethane elastomer has a solidification start temperature of at least 65 ° C. measured by a differential scanning calorimeter (DSC), and is measured by attaching a 100 μm aperture to a particle size distribution analyzer based on a pore electric resistance method. The number of particles of the polar solvent-insoluble component is 3,000,000 particles / g or less, and the fiber has a value (Sn / X _ave ) obtained by dividing the standard deviation (Sn) of the fiber diameter by the average fiber diameter (X _ave ) of 0. .15 or less.

The thermoplastic polyurethane elastomer for spun bond molding according to the present invention has a solidification start temperature of 65 ° C. or more measured by a differential scanning calorimeter (DSC) and a particle size distribution measuring device based on a pore electric resistance method of 100 μm. The number of particles of the polar solvent-insoluble component measured by attaching the aperture is 3,000,000 / g or less;
It is possible to produce a spunbonded stretchable nonwoven fabric having a value (Sn / X _ave ) obtained by dividing the standard deviation (Sn) of the fiber diameter by the average fiber diameter (X _ave ) of 0.15 or less. Features.

  According to the present invention, by using a polymer containing a thermoplastic polyurethane elastomer having a specific range of solidification start temperature and polar solvent insoluble content, yarn breakage, fusion of fibers and fusion to a spinning tower during spunbond molding. And spinning can be performed stably. Further, a spunbonded nonwoven fabric having a narrow fiber diameter distribution and excellent tactile sensation can be obtained.

(Stretchable nonwoven fabric)
The stretchable nonwoven fabric according to the present invention is a stretchable nonwoven fabric obtained by spunbonding a polymer containing a thermoplastic polyurethane elastomer having a specific range of a solidification initiation temperature and a polar solvent insoluble content, and the fiber diameter distribution is specified. Is a stretchable non-woven fabric in the range.

<Thermoplastic polyurethane elastomer>
The thermoplastic polyurethane elastomer (TPU) used in the present invention has a coagulation initiation 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). The temperature of the TPU is raised to 230 ° C. at 10 ° C./min, held at 230 ° C. for 5 minutes, and then maintained at 10 ° C. This is the starting temperature of the exothermic peak resulting from the solidification of the TPU that occurs when the temperature is decreased at a rate of / minute. When the solidification start temperature is 65 ° C. or higher, fusion defects between fibers during spunbond molding, yarn breakage, molding defects such as resin lumps can be suppressed, and molding is performed during hot embossing. The nonwoven fabric can be prevented from winding around the embossing roller. Further, the obtained nonwoven fabric has less stickiness, and is suitably used, for example, as a material which comes into contact with the skin, such as clothing, sanitary materials, and sports materials. On the other hand, by setting the solidification start temperature to 195 ° C. or lower, moldability can be improved. 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 the TPU to 65 ° C. or higher, the polyol, the isocyanate compound, and the chain extender used as the raw materials of the TPU are selected from those having optimal chemical structures, and the amount of the hard segment is adjusted. Need to adjust. here,
The hard segment amount is a weight percent (% by weight) value obtained by dividing the total weight of the isocyanate compound and the chain extender used in the production of the TPU by the total amount of the polyol, the isocyanate compound and the chain extender and multiplying by 100. is there. The amount of the 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 content of 3,000,000 particles / g or less, preferably 2.5 million or less, and most preferably 2 million or less. Here, the polar solvent insolubles in the TPU are mainly lumps such as fish eyes and gels generated during the production of the TPU, components derived from TPU hard segment aggregates, and hard segments and / or hard segments. Alternatively, it is a raw material constituting the TPU and a component generated by a chemical reaction between the raw materials, such as a component in which a soft segment is crosslinked by an allophanate bond, a burette bond, or the like.

  The number of particles of the polar solvent insoluble component is determined by measuring the insoluble content of TPU dissolved in a dimethylacetamide solvent (hereinafter abbreviated as “DMAC”) by a 100 μm aperture in a particle size distribution analyzer using a pore electric resistance method. Is a value measured by mounting the. When an aperture of 100 μm is attached, the number of particles of 2 to 60 μm in terms of uncrosslinked polystyrene can be measured. The present inventor has found that particles in this range have a close relationship with the spinning stability of fibers using TPU and the quality of stretch nonwovens. That is, by setting the number of particles of the polar solvent-insoluble component to 3 million or less per 1 g of TPU, problems such as an increase in fiber diameter distribution and yarn breakage during spinning within the above-mentioned TPU solidification start temperature range can be solved. Can be avoided. Further, the nonwoven fabric formed by using such a TPU can have a fiber diameter equal to that of a woven fabric and has an excellent tactile sensation, and thus can be suitably used as, for example, a sanitary material. Further, the filter installed inside the extruder for filtering impurities and the like is hardly clogged, and the frequency of adjustment and maintenance of equipment is reduced, which is industrially preferable.

  The TPU having a low polar solvent-insoluble content can be obtained by performing a polymerization reaction of a polyol, an isocyanate compound and a chain extender and then filtering the TPU, as described later.

The TPU has a total (a) of heat of fusion determined from an endothermic peak having a peak temperature in a range of 90 ° C. or more and 140 ° C. or less measured by a differential scanning calorimeter (DSC), and a peak temperature exceeding 140 ° C. (B) of the heat of fusion determined from the endothermic peak in the range of 220 ° C. or less
a / (a + b) × 100 ≦ 80 (1)
Preferably satisfy the relationship
The following equation (2)
a / (a + b) × 100 ≦ 70 (2)
More preferably, the relationship of
The following equation (3)
a / (a + b) × 100 ≦ 55 (3)
It is most preferable to satisfy the following relationship.

  Here, “a / (a + b) × 100” means the ratio of the heat of fusion of the hard domain of the TPU (unit:%). When the heat of fusion ratio of the hard domains of the TPU 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 the 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, most preferably 1000 to 1500 Pa · s at a temperature of 200 ° C. and a shear rate of 100 sec ⁻¹ . Here, the melt viscosity is a value measured by a capillograph (a product having a nozzle length of 30 mm and a diameter of 1 mm manufactured by Toyo Seiki Co., Ltd.).

  Further, the TPU preferably has a water content of 350 ppm or less, more preferably 300 ppm or less, and most preferably 150 ppm or less. By setting the water content to 350 ppm or less, it is possible to suppress the incorporation of air bubbles into the strands or the occurrence of yarn breakage in the formation of the nonwoven fabric with a large-scale spunbond molding machine.

<Production method of thermoplastic polyurethane elastomer>
As described above, the thermoplastic polyurethane elastomer used in the present invention is produced by selecting a polyol, an isocyanate compound and a chain extender each having an optimum chemical structure. As a method for producing the TPU, (i) a method of reacting an isocyanate group-terminated prepolymer (hereinafter, simply referred to as “prepolymer”) in which a polyol and an isocyanate compound are reacted in advance and a chain extender (hereinafter, referred to as “the prepolymer”) (Ii) a method in which a polyol and a chain extender are preliminarily mixed, and then the mixture is reacted with an isocyanate compound (hereinafter, referred to as a "one-shot method"). Among these production methods, it is preferable to produce a 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 the chain elongation are added at a ratio such that the isocyanate index is preferably in the range of 0.9 to 1.2, more preferably 0.95 to 1.15, and still more preferably 0.97 to 1.08. Stir at high speed and mix well. 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 to be used and the viscosity of the prepolymer, but is usually about 80 to 300 ° C., preferably 80 to 260 ° C. , Most preferably in the range of 90 to 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 previously mixed 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 allowed to proceed 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 manufacturing equipment>
The TPU manufacturing apparatus is an apparatus for continuously manufacturing a thermoplastic polyurethane elastomer by a reactive extrusion 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 a storage tank for an isocyanate compound, a storage tank for a polyol, and a storage tank for a chain extender. Each storage tank is connected to a high-speed stirrer or a static mixer section to be described later via each supply line, and a gear pump and a flow meter downstream of the gear pump are provided in the middle of each supply line.

  The mixing section is provided with mixing means such as a high-speed stirrer. The high-speed stirrer is not particularly limited as long as the above-mentioned raw materials can be stirred and mixed at a 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 rotations / minute (peripheral speed) (100 to 600 m / min), preferably 1000 to 3500 rpm (peripheral speed 120 to 420 m / min). The high-speed stirrer preferably includes a heater (or a jacket) and a temperature sensor, and preferably controls the heater based on the temperature detected by the temperature sensor to control the temperature in the stirring tank.

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

  The static mixer section is preferably configured by connecting a plurality of static mixers (stationary mixers) in series. Each static mixer (hereinafter, when each static mixer is distinguished, the first static mixer 1, the second static mixer 2,... n) is not particularly limited with respect to the shape of the internal mixer member. For example, “Advances in Chemical Engineering Vol. 24, Stirring / Mixing” (edited by the Society of Chemical Engineers, Tokai Branch, edited by Maki, October 20, 1990) FIG. Various shapes such as a Company-N type, a Company-T type, a Company-S type, and a 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 each static mixer as needed.

  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 13 to 150 mmφ, more preferably 15 to 50 mmφ, and a tube length / inner diameter ratio (hereinafter referred to as L / D) of usually 3 to 25, preferably 5 to 15 is used. Further, each static mixer has at least a portion where the contact with the reaction raw material is formed of a substantially non-metallic material such as fiber reinforced plastic (FRP), or the surface of the contact portion with the reaction raw material is, for example, polytetrafluoroethylene. It is preferable to use one 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 nonmetallic material, it is possible to effectively prevent the generation of the polar solvent insolubles in the TPU. Specific examples of such a static mixer include a metal static mixer whose inner wall is protected by a fluororesin tube such as polytetrafluoroethylene, and a commercially available MX series manufactured by Noritake Company Limited. No.

  Further, each static mixer is preferably provided with a heater (or a jacket) and a temperature sensor individually, and is preferably capable of controlling the heater based on the temperature detected by the temperature sensor and independently controlling the temperature in the mixer. Thereby, the temperature in the tube of each static mixer can be changed according to the composition of the reaction raw material, and the amount of the catalyst can be reduced, and the TPU can be manufactured under optimal 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 a pelletizing section described later. Or it is connected to a single screw extruder. The number of connected static mixers can be appropriately determined according to the purpose and use of the TPU, the raw material composition, and the like. For example, the respective static mixers are connected such that the total length of the static mixer section is usually 3 to 25 m, preferably 5 to 20 m, and the number of connections is, for example, 10 to 50, preferably 15 to 35. . The flow rate may be adjusted by appropriately interposing a gear pump between the static mixers.

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

  A single screw extruder for further kneading the reaction product flowing out of 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, a reaction mixture of at least an isocyanate compound and a polyol in advance and a chain extender are allowed to undergo a polymerization reaction of these reaction raw materials while passing through a static mixer. In particular, it is preferable to sufficiently stir and mix the isocyanate compound and the polyol with a high-speed stirrer, further stir and mix this mixture with a chain extender with a high-speed stirrer, and then to carry out a polymerization reaction in a static mixer. Alternatively, a prepolymer is prepared by mixing an isocyanate compound and a polyol and reacting them, and after mixing this prepolymer and a chain extender with a high-speed stirrer, a polymerization reaction can be performed in a static mixer.

  The mixture is a mixture of an isocyanate compound and a polyol 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 It is prepared by high speed stirring at 140 ° C. When the mixture is retained in a reaction pot to promote prepolymerization, 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 minutes. ° C, preferably 90 to 140 ° C.

  The thus-prepared mixture and the chain extender are supplied to a static mixer, and they are polymerized. The mixture and the chain extender may be independently supplied to a static mixer, or may be mixed in advance with a high-speed stirrer and then supplied to the static mixer. Alternatively, a prepolymer may be prepared in advance by reacting an isocyanate compound with a polyol, and the prepolymer and a chain extender may be supplied to a static mixer to cause a polymerization reaction between them. The temperature in the static mixer is usually 100 to 300 ° C, preferably 150 to 280 ° C. It is desirable to set the passage speed of the reaction raw materials and reaction products to 10 to 200 kg / h, preferably 30 to 150 kg / h.

  The TPU used in the present invention may be prepared by, for example, thoroughly stirring and mixing an isocyanate compound, a polyol and a chain extender in advance with a high-speed stirrer, continuously flowing the mixture on a belt, and heating the TPU. TPU can also be produced by polymerization.

  By producing a TPU by these production methods, it is possible to obtain a TPU with a low polar solvent insoluble content such as fish eye. Further, by filtering the obtained TPU, the insoluble matter in the polar solvent can be reduced. For example, after the TPU pellets are sufficiently dried, fish eyes can be filtered through an extruder provided with a filter material such as a metal mesh, a metal nonwoven fabric, or a polymer filter at the tip. The lower limit of the polar solvent insoluble content in the TPU thus obtained is about 30,000 / g. The extruder is preferably a single or multiple screw extruder. The mesh size of the metal mesh is usually at least 100 mesh, preferably at least 500 mesh, more preferably at least 1000 mesh. Further, it is preferable to use a plurality of metal meshes having the same mesh size or different mesh sizes in a stacked state. As the polymer filter, for example, Fuji Duplex polymer filter system (manufactured by Fuji Filter Industry Co., Ltd.), Asuka polymer filter system (manufactured by Asuka Industry Co., Ltd.), and Denafilter (manufactured by Nagase Sangyo Co., Ltd.) No.

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

<Polyol>
The polyol used for producing the above 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 as a mixture of two or more. Among these polyols, polyoxyalkylene polyol, polytetramethylene ether glycol, and polyester polyol are preferred.

  It is preferable that these polyols are sufficiently subjected to dehydration under heat and reduced pressure to reduce water content. The water content of these polyols is preferably 0.05% by weight or less, more preferably 0.03% by weight or less, and further preferably 0.02% by weight or less.

(Polyoxyalkylene polyol)
Examples of the polyoxyalkylene polyol include a polyoxyalkylene glycol obtained by addition-polymerizing one or more dihydric alcohols having a relatively low molecular weight with an alkylene oxide such as propylene oxide, ethylene oxide, butylene oxide, and styrene oxide. Can be 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. When two or more alkylene oxides are used, it is preferable that propylene oxide accounts for 40% by weight or more, more preferably 50% by weight or more of the total amount. By using an alkylene oxide containing the above ratio of propylene oxide, the content of oxypropylene groups in the polyoxyalkylene polyol can be increased to 40% by weight or more.

  Further, in order to improve the durability and mechanical properties of TPU, the primary hydroxyl group conversion rate at the molecular terminal of the polyoxyalkylene polyol is desirably 50 mol% or more, and more desirably 60 mol% or more. In order to improve the primary hydroxyl group conversion, it is preferable to copolymerize ethylene oxide at the molecular terminal.

  The number average molecular weight of the polyoxyalkylene polyol used for producing the above 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 the TPU and improving the flow characteristics, it is preferable to produce a TPU by mixing two or more polyoxyalkylene polyols having different molecular weights and different oxyalkylene group contents. In the polyoxyalkylene polyol, it is preferable that a monool having an unsaturated group at a molecular terminal generated by a side reaction of propylene oxide addition polymerization is small. The monol content in the polyoxyalkylene polyol is represented by the total degree of unsaturation described in JIS K-1557. The total degree of unsaturation 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 exceeds 0.03 meq / g, the heat resistance and durability of the TPU tend to decrease. Further, the lower limit of the total unsaturation is preferably about 0.001 meq / g from the viewpoint of industrial production of the polyoxyalkylene polyol.

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

(Polyester polyol)
Examples of the polyester polyol include a polyester polyol obtained by condensation polymerization of one or more low molecular weight polyols with one or more carboxylic acids such as low molecular weight dicarboxylic acids and oligomeric 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, triglycol, and the like. Examples include methylolpropane, 3-methyl-1,5-pentanediol, hydrogenated bisphenol A, hydrogenated bisphenol F, and the like. Examples of the low molecular weight dicarboxylic acid include glutaric acid, adipic acid, sebacic acid, terephthalic acid, isophthalic acid, dimer acid and the like. 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)
Polycaprolactone polyol can be obtained by ring-opening polymerization of ε-caprolactone.

(Polycarbonate diol)
Examples of the polycarbonate diol include a polycarbonate diol obtained by a condensation reaction of a dihydric alcohol such as 1,4-butanediol and 1,6-hexanediol with 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, and particularly preferably about 800 to 2,000.

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

(Aromatic polyisocyanate)
As the aromatic polyisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, an isomer mixture of tolylene diisocyanate at a weight ratio (2,4-form: 2,6-form) of 80:20 ( TDI-80 / 20), 65:35 weight ratio (2,4-form: 2,6-form) isomer mixture of tolylene diisocyanate (TDI-65 / 35); 4,4′-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, and any mixture of isomers 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-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, , 5,7-Trimethyl-1,8-diisocyanate-5-isocyanatomethyloctane, bis (isocyanateethyl) carbonate, bis (isocyanateethyl) ether, 1,4-butyleneglycoldipropylether-ω, ω′-diisocyanate, Lysine isocyanate methyl ester, lysine triisocyanate, 2-isocyanatoethyl-2,6-diisocyanate hexanoate, 2-isocyanatopropyl-2,6-diisocyanate hexanoate, bis And 4-isocyanate -n- butylidene) pentaerythritol.

(Alicyclic polyisocyanate)
Examples of the alicyclic polyisocyanate include isophorone diisocyanate, bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, 2,2′-dimethyldicyclohexylmethane diisocyanate, dimer diisocyanate, and 2,5-diisocyanate. Methyl-bicyclo [2.2.1] -heptane, 2,6-diisocyanatomethyl-bicyclo [2.2.1] -heptane, 2-isocyanatomethyl-2- (3-isocyanatopropyl) -5-isocyanatomethyl- 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 2.2.1] -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, carbodiimide-modified, uretoimine-modified, biuret-modified, allophanate-modified and isocyanurate-modified polyisocyanate can also 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”) Abbreviated), naphthalenediisocyanate (hereinafter abbreviated as “NDI”), hexamethylene diisocyanate (hereinafter abbreviated as “HDI”), isophorone diisocyanate (hereinafter abbreviated as “IPDI”), 2,5-diisocyanatomethyl-bicyclo [ 2.2.1] -heptane (hereinafter abbreviated as “2,5-NBDI”), 2,6-diisocyanatomethyl-bicyclo [2.2.1] -heptane (hereinafter “2,6-NBDI”) Abbreviated) is preferably used. More preferably, MDI, HDI, HMDI, PPDI, 2,5-NBDI, 2,6-NBDI and the like are used. In addition, urethane-modified, carbodiimide-modified, uretoimine-modified, and isocyanurate-modified 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 under reduced pressure to reduce water content. The water content of the chain extender is preferably 0.05% by weight or less, more preferably 0.03% by weight or less, and further 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, and trimethylolpropane. Can be Examples of aromatic, heterocyclic or alicyclic polyols include para-xylene glycol, bis (2-hydroxyethyl) terephthalate, bis (2-hydroxyethyl) isophthalate, and 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 alone or in a combination of two or more.

<Catalyst>
In producing the TPU, a known catalyst used in producing polyurethane such as an organometallic compound may be added. Of the known catalysts, organometallic compounds are preferred, for example, tin acetate, tin octylate, tin oleate, tin laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, lead octanoate, lead naphthenate, Nickel naphthenate, cobalt naphthenate and the like. These catalysts may be used alone or in a combination of two or more. The amount of the catalyst is usually 0.0001 to 2.0 parts by weight, preferably 0.001 to 1.0 parts by weight, based on 100 parts by weight of the polyol.

<Additives>
It is preferable to add a heat stabilizer and a light stabilizer to the TPU used in the present invention. These stabilizers can be added both at the time of production of the TPU and after the production, but it is preferable that the stabilizer is previously dissolved in the reaction raw materials at the time of the production of the TPU.

  Examples of the heat stabilizer include a hindered phenol-based antioxidant, a phosphorus-based heat stabilizer, a lactone-based heat stabilizer, and a sulfur-based heat stabilizer. More specifically, for example, IRGANOX1010, 1035, 1076, 1098, 1135, 1222, 1425WL, 1520L, 245, 3790, 5057, IRGAFOS168, 126, HP-136 (or more) , Trade name, Ciba Specialty Chemicals Co., Ltd.) and the like are preferably used.

  Examples of the light stabilizer include a benzotriazole-based ultraviolet absorber, a triazine-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, a benzoate-based light stabilizer, and a hindered amine-based light stabilizer. More specifically, for example, TINUVIN P, 234, 326, 327, 328, 329, 571, 144, 765, B75 (trade names, Ciba Specialty Chemicals, Inc.) )) Is preferably used.

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

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

<Polymer>
When producing the stretchable nonwoven fabric according to the present invention, the above-mentioned thermoplastic polyurethane elastomer can be used alone as a polymer.However, as long as the object of the present invention is not impaired, other thermoplastic polymers may be used as needed. They can be used in combination. When the thermoplastic polyurethane elastomer is used in combination with another thermoplastic polymer, the content of TPU is preferably 10% by weight or more, more preferably 50% by weight or more, still more preferably 65% by weight or more. Most preferred is at least weight percent. By using a polymer having a TPU content of 10% by weight or more, a stretchable nonwoven fabric having sufficient elasticity and a low residual strain rate can be obtained. For example, the stretchability of clothing, sanitary materials, sports materials, and the like is required. It can be preferably used as a material to be used.

(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; PVC elastomers; polyesters; ester elastomers; polyamides; amide elastomers; polyolefins such as polyethylene, polypropylene and polystyrene;

  Styrene-based 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. Examples of the styrene-based elastomer include 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.) and the like.

  Examples of the polyolefin-based elastomer include an ethylene / α-olefin copolymer and a propylene / α-olefin copolymer. For example, TAFMER (trade name, manufactured by Mitsui Chemicals, Inc.), ethylene-octene copolymer Engage (trade name, manufactured by DuPont Dow Elastomers), and crystalline olefin copolymer CATALLOY (trade name, manufactured by Montell Corporation) And the like.

  Examples of the PVC elastomer include Leonil (trade name, manufactured by Riken Technos Co., Ltd.) and Posmir (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-based elastomer include PEBAX (trade name, Atofina Japan K.K.).

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

  Such other thermoplastic polymers may be blended with TPU in a molten state, pelletized and spun, or may be blended with TPU in a pellet state and spun.

(Additive)
Various stabilizers such as heat stabilizers and weather stabilizers; antistatic agents, slip agents, antifogging agents, lubricants, dyes, pigments, natural oils, synthetic oils, waxes, etc. are added to the polymer used in the present invention. be able to.

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

<Elastic nonwoven fabric>
The stretchable nonwoven fabric according to the present invention is produced by spunbonding a polymer containing the thermoplastic polyurethane elastomer. As the spun bond molding method used here, a conventionally known method can be applied, for example, a method described in JP-A-60-155765. Specifically, the polymer is melt spun from a spinning nozzle to form a large number of fibers. At this time, when the TPU and another thermoplastic polymer are used in combination as the polymer, composite fibers such as a core-sheath type, a split type, a sea-island type, and a side-by-side type may be formed. Here, the conjugate fiber refers to a fiber in which the ratio of the length to the diameter when the cross section is assumed to be a circle is such that two or more phases are appropriate to be called the fiber. The core-sheath type composite fiber is a concentric type in which the center point of a circular core is the same as the center point of a donut-shaped sheath in the fiber cross section; the center point of the core and the center point of the sheath are Either of the eccentric type in which the center is different from the center of the core and the center of the sheath is different, and a part of the core is exposed on the side of the fiber. It may be.

  The fibers are introduced into a cooling chamber, cooled by cooling air, then drawn by drawing air, and deposited on a moving collecting surface. In the above production method, the temperature of the die having the spinning nozzle is usually from 180 to 240C, preferably from 190 to 230C, more preferably from 200 to 225C. The cooling air temperature is usually from 5 to 50 ° C, preferably from 10 to 40 ° C, more preferably from 15 to 30 ° C, from the viewpoint of economy and spinnability. The stretching air velocity is usually 100 to 10,000 m / min, preferably 500 to 10,000 m / min.

The fiber diameter of the nonwoven fabric thus obtained is usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. The fibers of this nonwoven fabric have smaller fiber diameter variations than the meltblown molded nonwoven fabric. Specifically, a value obtained by dividing the standard deviation of fiber diameter (Sn) by the average fiber diameter _{(X ave) (Sn / X} ave) is 0.15 or less, preferably 0.12 or less, more preferably 0.10 It is as follows. When Sn / X _ave is reduced, unevenness on the surface of the nonwoven fabric is reduced, and the feel is significantly improved.

  Next, after the fibers are deposited in a web shape on the moving collection surface by the above method, the deposits are subjected to a confounding treatment using a needle punch, a water jet, an ultrasonic seal or the like, or a heat fusion treatment using a hot embossing roll. To partially fuse the deposit. At this time, a heat fusion treatment using a hot embossing roll is preferably used. The embossing temperature is usually 50 to 160C, preferably 70 to 150C. The embossing area ratio of the embossing roll can be appropriately determined, but is preferably 5 to 30%.

  By performing the heat embossing as described above, unlike the conventional nonwoven fabric by melt blown molding in which the fibers themselves are joined by their own heat, the fibers are joined together mechanically and firmly, so that the tensile strength, the maximum strength, and the fracture Physical properties such as elongation at the time are significantly improved. In addition, the embossed region is less likely to be broken during elongation, and the residual strain rate is reduced.

  Such a nonwoven fabric has excellent elasticity, and is preferably used for applications that directly touch the skin, such as clothing, sanitary materials, and sports materials. Examples of sanitary materials include disposable diapers, sanitary napkins, urine collecting pads, and the like.

  The tensile strength per unit weight of the elastic nonwoven fabric at 100% elongation is usually 1 to 50 gf / unit weight, preferably 1.5 to 30 gf / unit weight, and more preferably 2 to 20 gf / unit unit weight. When the tensile strength is 1 gf / basis or more, when the stretchable nonwoven fabric is used for, for example, clothing, sanitary materials, sports materials, and the like, a good fit to the human body can be ensured.

  The maximum strength per unit weight of the elastic nonwoven fabric is usually 5 to 100 gf / unit weight, preferably 10 to 70 gf / unit weight, and more preferably 15 to 50 gf / unit unit weight. When the maximum strength is 5 gf / basis or more, when the stretchable nonwoven fabric is used, for example, in clothing, sanitary materials, sports materials, and the like, it becomes difficult to break.

  The maximum point elongation of the stretchable nonwoven fabric is usually 50 to 1200%, preferably 100 to 1000%, and more preferably 150 to 700%. By setting the maximum point elongation to 50% or more, a good wearing feeling can be imparted when the stretchable nonwoven fabric is used for clothing, sanitary materials, sports materials and the like, for example.

  The stretchable 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 less noticeable.

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

(Laminate)
The stretchable nonwoven fabric according to the present invention can be combined with an extensible nonwoven fabric to form a stretched laminate having a more excellent tactile sensation.

  The stretchable nonwoven fabric is not particularly limited as long as it can follow the maximum elongation of the stretchable nonwoven fabric, but when the laminate is used for a sanitary material such as a disposable diaper, it has a good feel and a high feel. Since stretchability and excellent heat sealing properties 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 hot embossing, the stretchable nonwoven fabric is preferably a nonwoven fabric made of a polymer having good compatibility and adhesiveness with the stretchable nonwoven fabric according to the present invention.

  The fiber forming the extensible nonwoven fabric is preferably, for example, a monocomponent fiber, a core-sheath fiber, a split fiber, a sea-island fiber, or a side-by-side fiber, or a mixed fiber thereof.

Such an elastic laminate is manufactured by the following method. After the stretchable fiber is deposited on the collecting surface by the above method, the stretchable fiber is deposited on the deposit. Thereafter, the same entanglement treatment or heat fusion treatment as described above is performed to obtain a laminate including a stretchable nonwoven fabric layer and an extensible nonwoven fabric layer. Such a laminate can also be obtained by joining a stretchable nonwoven fabric and an extensible nonwoven fabric with an adhesive.

  The conditions for the hot embossing are preferably the same as those described above. Examples of the adhesive include resin adhesives such as vinyl acetate, vinyl chloride, and polyvinyl alcohol; and rubber adhesives such as styrene butadiene, styrene-isoprene, and urethane. Further, a solvent-based adhesive obtained by dissolving these adhesives in an organic solvent, an aqueous emulsion adhesive obtained by emulsification, and the like can be used. Among these adhesives, rubber-based hot melt adhesives such as styrene-isoprene-based and styrene-butadiene-based adhesives are preferably used because they do not impair the good feel.

  Further, as the laminate according to the present invention, a laminate obtained by laminating a thermoplastic polymer film on a layer made of the elastic nonwoven fabric is exemplified. The thermoplastic polymer film may be a breathable film or a perforated film.

[Example]
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples. The analysis and evaluation of TPU in Examples and Comparative Examples were performed according to the following methods.

(1) Solidification onset temperature Measured by a differential scanning calorimeter (DSC220C) connected to an SSC5200H disk station manufactured by Seiko Denshi Kogyo KK As a sample, about 8 mg of the crushed TPU was collected in an aluminum pan, covered, and crimped. Alumina was similarly collected as a reference. After setting the sample and reference at predetermined positions in the cell, the measurement was performed under a nitrogen stream at a flow rate of 40 Nml / min. The temperature was raised from room temperature to 230 ° C. at a rate of 10 ° C./min, held at this temperature for 5 minutes, and then lowered to −75 ° C. at a rate of 10 ° C./min. The start temperature of the exothermic peak due to the solidification of the TPU recorded at this time was measured and defined as the solidification start temperature (unit: ° C).

(2) Number of particles insoluble in polar solvent The measurement was carried out using a Multisser II manufactured by Beckman Coulter, Inc. as a particle size distribution measuring device based on the pore electric 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 left at room temperature for 24 hours. To dissolve. Next, filtration under reduced pressure was performed with a 1 μm membrane filter to obtain a reagent A. 180 g of the reagent A and 2.37 g of TPU pellets were precisely weighed in a 200 cc glass bottle, and the soluble matter in the TPU was dissolved over 3 hours to prepare a sample for measurement. A 100 μm aperture tube was attached to Multisizer II, the solvent in the apparatus was replaced with reagent A, and then the degree of vacuum was adjusted to about 3000 mmAq. 120 g of the reagent A was weighed into a well-washed beaker for charging a sample, and it was confirmed that the pulse rate generated by the blank measurement was 50 pulses / min or less. After manually setting the optimal Current value and Gain, calibration was performed using 10 μm uncrosslinked polystyrene standard particles. The measurement was carried out for 210 seconds by weighing 120 g of the reagent A and about 10 g of the measurement sample in a well-washed sample beaker. The value obtained by dividing the number of particles counted by this measurement by the weight of the TPU sucked into the aperture tube was defined as the number of particles (unit: particles / g) insoluble in the polar solvent in the TPU. The TPU weight was calculated by the following equation.

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

(3) Melting heat ratio of hard domain Measured by a differential scanning calorimeter (DSC220C) connected to an SSC5200H disk station manufactured by Seiko Electronics Industry Co., Ltd. As a sample, about 8 mg of the crushed TPU was collected in an aluminum pan, covered, and crimped. Alumina was similarly collected as a reference. After setting the sample and reference at predetermined positions in the cell, the measurement was performed under a nitrogen stream at a flow rate of 40 Nml / min. The temperature was raised from room temperature to 230 ° C. at a rate of 10 ° C./min. At this time, the total (a) of the heat of fusion determined from the endothermic peak whose peak temperature is in the range of 90 ° C. or more and 140 ° C. or less, and the endothermic peak whose peak temperature is in the range of more than 140 ° C. and not more than 220 ° C. The sum (b) of the heats of fusion was determined, and the heat of fusion ratio (unit:%) of the hard domains was determined by the following equation.

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

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

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

(7) Average minimum fiber diameter Melt spinning is performed under the same conditions as in the production of the non-woven fabric except for the drawing air velocity, and the drawing air velocity is increased by 250 m / min until a yarn break occurs. The stretched air wind speed 250 m / min slower than the air wind speed was determined. Except for the drawing air speed, the same conditions as in the production of the nonwoven fabric were used, and the melt spinning was performed at the drawing air speed determined as described above, and the fibers were deposited to form a web. 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 by image size measurement software (Pixs2000 Version 2.0, manufactured by Inotech). The diameter of 100 fibers was measured, and the average minimum fiber diameter (unit: μm) was determined.

(8) Average Fiber Diameter, Standard Deviation For the examples, the obtained nonwoven fabric was photographed at a magnification of 200 times by an electron microscope. On the other hand, in Comparative Example, the broken or fused portion of the nonwoven fabric was photographed at a magnification of 200 times. The diameter (Xi, unit: μm) of 100 fibers was measured from these images, and the average fiber diameter (X _ave , unit: μm) was determined. The standard deviation (Sn, unit: μm) was determined by the following equation (n = 100).

(9) Number of yarn breaks The spinning situation near the nozzle surface was visually observed, and the number of yarn breaks per 5 minutes (unit: times / 5 min) was counted. Here, the phenomenon that one fiber is cut alone during molding is defined as a single yarn break, and when fibers are fused together and the fiber breaks, it is not included as fiber fusion. Shall be.

(10) Number of fusions The spinning situation near the nozzle surface was visually observed, and the number of fusions of the fiber per 5 minutes (unit: times / 5 min) was counted.

(11) Maximum strength, maximum point elongation Five test pieces having a flow direction (MD) of 5.0 cm and a transverse direction (CD) of 2.5 cm were cut from the obtained nonwoven fabric. The test piece was stretched under the conditions of a chuck distance of 30 mm and a tensile speed of 30 mm / min, and the elongation at the maximum load was determined. This tensile test was performed on five test pieces, and the average value of the elongation at the maximum load was defined as the maximum point elongation (unit:%), and the value obtained by dividing the average value of the maximum load by the basis weight was used as the maximum strength (unit). : Gf / basis weight).

(12) residual strain, tensile strength,
Five test pieces having a flow direction (MD) of 5.0 cm and a transverse direction (CD) of 2.5 cm were cut from the obtained nonwoven fabric. The test piece was stretched under the conditions of a chuck distance of 30 mm, a tensile speed of 30 mm / min, and a stretching ratio of 100%, and the load at this time was measured. Then, it was immediately restored to the original length at the same speed, and the strain at the time when the tensile load became 0 gf was measured. This tensile test was carried out on five test pieces, the value obtained by dividing the average value of the load at 100% elongation by the basis weight as the tensile strength (unit: gf / basis weight), and the average value of the strain as the residual strain (unit: %).

(13) Touch Feeling The touch feeling of the obtained nonwoven fabric was evaluated. Ten panelists confirmed the feel of the nonwoven fabric and evaluated according to the following criteria.
A: When 10 out of 10 people felt that there was no stickiness and the feel was good.
B: 9 to 7 persons out of 10 felt sticky and felt good to touch.
C: 6 to 3 persons out of 10 felt sticky and felt good.
D: 2 to 0 out of 10 persons felt that there was no stickiness and the feel was good.

<TPU Production Example 1>
280.3 parts by weight of 4,4′-diphenylmethane diisocyanate (trade name: Cosmonate PH, manufactured by Mitsui Takeda Chemical Co., Ltd .; hereinafter, referred to as “MDI”) was placed in an isocyanate compound storage tank (hereinafter, referred to as tank A). The mixture was charged in a nitrogen atmosphere, and the temperature was adjusted to 45 ° C. while stirring to the extent that bubbles did not mix.

219.8 parts by weight of a polyester polyol having a number average molecular weight of 1000 (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name: Takelac U2410) and a polyester polyol having a number average molecular weight of 2000 (manufactured by Mitsui Takeda Chemical Co., trade name: Takerac U2420) ) 439.7 parts by weight, 2.97 parts by weight of bis (2,6-diisopropylphenyl) carbodiimide (manufactured by RASCHIG GmbH, trade name: Stabilizer 7000), and a hindered phenol-based antioxidant (Ciba Specialty Chemicals) Company, trade name: Irganox 1010) 2.22 parts by weight and a benzotriazole-based UV absorber (manufactured by Johoku Chemical Co., Ltd., trade name: JF-83) 2.22 parts by weight were added to a polyol storage tank (hereinafter, referred to as JF-83) , Tank B) under a nitrogen atmosphere and stirring. The temperature was adjusted to 90 ° C. This mixture is referred to as polyol solution 1.

  Under a nitrogen atmosphere, 60.2 parts by weight of a chain extender 1,4-butanediol (manufactured by BASF Japan Co., Ltd.) was charged into a chain extender storage tank (hereinafter referred to as tank C) 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. at a flow rate of 16.69 kg / h for the MDI and a flow rate of 39.72 kg / h for the polyol solution 1 in a liquid sending line via a gear pump and a flow meter was used. ) Quantitatively passed through Sakura Plant, Model: SM40), stirred and mixed at 2000 rpm for 2 minutes, and then sent to a reaction pot with a stirrer adjusted to 120 ° C. Further, this mixed solution was quantitatively supplied to a high-speed stirrer (SM40) in which 1,4-butanediol was adjusted to 120 ° C. at a flow rate of 56.41 kg / h from tank C at a flow rate of 3.59 kg / h from tank C. The solution was passed and stirred and mixed at 2000 rpm for 2 minutes. Thereafter, the mixture 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 section was connected to three 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.), seventh to twelfth static mixers (temperature 210 ° C.) connected to six static mixers having a pipe length of 1.0 m and an inner diameter of 34 mmφ, a pipe length of 0.5 m, The thirteenth to fifteenth static mixers (temperature: 200 ° C.) in which three static mixers having an inner diameter of 38 mmφ are connected in series.

  The reaction product flowing out of the fifteenth static mixer was passed, via a gear pump, to a single-screw extruder (diameter 65 mmφ, temperature 200 to 215) having a polymer filter (trade name: Dena Filter, manufactured by Nagase & Co., Ltd.) at the tip. ° C) and extruded from a strand die. After water cooling, the mixture 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 water content 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 / g, the hardness of a test piece prepared by injection molding is 86 A, the melt viscosity at 200 ° C. is 2100 Pa · s, The heat of fusion ratio of the domain was 62.8%.

<Example 2 of TPU production>
288.66 parts by weight of MDI was charged into tank A under a nitrogen atmosphere, and the temperature was adjusted to 45 ° C. while 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 (trade name: PTG-1000, manufactured by Hodogaya Chemical Co., Ltd.) and a polyester polyol having a number average molecular weight of 2000 (trade name, manufactured by Mitsui Takeda Chemical Co., Ltd.) : Bamboo rack U2720) 432.5 parts by weight, 2.22 parts by weight of Irganox 1010, and 2.22 parts by weight of JF-83 were charged into tank B under a nitrogen atmosphere, and the temperature was adjusted to 95 ° C. while stirring. . This mixture is called polyol solution 2.

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

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

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

  The reaction product flowing out of 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 water content of 70 ppm.

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

<TPU Manufacturing Example 3>
100 parts by weight of adipate-based polyester polyol (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name: Takelac U2410), 3.12 parts by weight of 1,4-butanediol, and 0.13 of an amide wax-based lubricant (stearic amide) A weight part and 0.38 part by weight of a weather resistance stabilizer (manufactured by Sankyo KK, trade name: Sanol LS-770) were charged into a pressure kneader under a nitrogen atmosphere and heated to 60 ° C. To this mixture, 22.46 parts by weight of 1,6-hexamethylene diisocyanate (trade name: Takenate 700, manufactured by Mitsui Takeda Chemical Co., Ltd.) was charged with stirring, and further stirred and mixed for 20 minutes. Next, this mixed solution was transferred to a stainless steel container, and reacted in an oven previously adjusted to 70 ° C. under a nitrogen atmosphere at 70 ° C. for 24 hours to obtain a TPU sheet. The sheet was gradually cooled to room temperature and pulverized with a granulator into flakes. Thereafter, the flakes were dried under reduced pressure to obtain a thermoplastic polyurethane elastomer (TPU-3) having a moisture value of 120 ppm.

  The solidification start temperature of TPU-3 was 55.2 ° C., the number of particles of the polar solvent-insoluble component was 3.5 million / g, and the hardness of a test piece prepared by injection molding was 86A. The flow start temperature measured by the method described in WO 99/39037 (page 9, lines 3 to 9) was 108 ° C.

<TPU Production Example 4>
MDI was charged into tank A under a nitrogen atmosphere, and the temperature was adjusted to 45 ° C. while stirring to the extent that air bubbles did not mix.

628.6 parts by weight of a polyester polyol having a number average molecular weight of 2,000 (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name: Takelac U2024), 2.21 parts by weight of Irganox 1010, and 77.5 parts by weight of 1,4-butanediol Were charged into a tank B under a nitrogen atmosphere, and the temperature was adjusted to 95 ° C. while stirring. This mixture is called polyol solution 3.

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

  Next, a high-speed stirrer (SM40) in which the MDI was adjusted to 120 ° C. at a flow rate of 17.6 kg / h and the polyol solution 3 at a flow rate of 42.4 kg / h through a liquid sending line via a gear pump and a flow meter. After the mixture was quantitatively passed through and stirred at 2,000 rpm for 2 minutes, the mixture was passed through a static mixer in the same manner as in Production Example 1. The static mixer section was connected to three static mixers (temperature: 230 ° C.) connected to three static mixers having a pipe length of 0.5 m and an inner diameter of 20 mmφ, 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.), seventh to twelfth static mixers (temperature 210 ° C.) connected to six static mixers having a pipe length of 1.0 m and an inner diameter of 34 mmφ, a pipe length of 0.5 m, The thirteenth to fifteenth static mixers (temperature: 200 ° C.) in which three static mixers having an inner diameter of 38 mmφ are connected in series.

  The reaction product flowing out of the fifteenth static mixer was passed through a gear pump to a single-screw extruder (diameter: 65 mmφ, temperature: 180 to 210) having a polymer filter (trade name: Dena Filter, manufactured by Nagase & Co., Ltd.) at the tip. ° C) and extruded from a strand die. After water cooling, the mixture 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 dried again at 100 ° C. for 7 hours to obtain a thermoplastic polyurethane elastomer (TPU-4) having a water content of 57 ppm.

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

After melting the TPU-1 prepared in Production Example 1 above, using a spun bond molding machine having a spinneret having a nozzle diameter of 0.6 mmφ, a nozzle pitch of 8 mm in a vertical direction and 8 mm in a horizontal direction, a die temperature of 220 ° C. Melt spinning was performed under the conditions of a hole discharge amount of 1.0 g / (minute / hole), a cooling air temperature of 20 ° C., and a drawing air speed of 3000 m / min, and a web made of TPU-1 was deposited on the collecting surface. This web is embossed at 80 ° C. (emboss area ratio: 7%, emboss roll diameter: 150 mmφ, engraving pitch: 2.1 mm in vertical and horizontal directions, engraved shape: rhombus), and spunbond having a basis weight of 100 g / m ² . A non-woven fabric was manufactured. Table 1 shows the evaluation results of the obtained nonwoven fabric.
Shown in

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

An ethylene / vinyl acetate / vinyl alcohol copolymer (manufactured by Mitsui Takeda Chemical Co., Ltd., trade name: Dumilan C1550) was previously dried at 70 ° C. for 8 hours using a dryer to adjust the water content to 78 ppm.

95 parts by weight of TPU-2 and 5 parts by weight of the ethylene / vinyl acetate / vinyl alcohol copolymer were blended in a molten state, and then pelletized. The solidification starting temperature of this blend polymer was 104.2 ° C., and the hardness of a test piece prepared by injection molding was 85A.

  A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that the above blended polymer was used instead of TPU-1. Table 1 shows the evaluation results of the obtained nonwoven fabric.

  A styrene-ethylene-propylene-styrene block copolymer (SEPS, manufactured by Kuraray Co., Ltd., trade name: Septon 2002) was previously dried at 80 ° C. for 8 hours using a drier to adjust the water content to 58 ppm. An ethylene / α-olefin copolymer (trade name: Tuffmer A-35050, manufactured by Mitsui Chemicals, Inc.) was previously dried at 75 ° C. for 8 hours using a drier to adjust the water content to 50 ppm.

  80 parts by weight of TPU-2, 15 parts by weight of Septon 2002, and 5 parts by weight of the ethylene / α-olefin copolymer were blended in a molten state, and then pelletized. The solidification starting temperature of this blend polymer was 98.2 ° C., and the hardness of a test piece prepared by injection molding was 85A.

  A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that the above blended polymer was used instead of TPU-1. Table 1 shows the evaluation results of the obtained nonwoven fabric.

  A styrene-ethylene-propylene-styrene block copolymer (SEPS, manufactured by Kuraray Co., Ltd., trade name: Septon 2004) was previously dried at 80 ° C. for 8 hours using a dryer to adjust the water content to 62 ppm.

  45 parts by weight of TPU-2 and 55 parts by weight of Septon 2004 were blended in a molten state and then pelletized. The solidification start temperature of this blend polymer was 90.7 ° C., and the hardness of a test piece prepared by injection molding was 82 A.

  A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that the above blended polymer was used instead of TPU-1. Table 1 shows the evaluation results of the obtained nonwoven fabric.

  A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1, except that TPU-4 was used instead of TPU-1. Table 1 shows the evaluation results of the obtained nonwoven fabric.

A spunbonded nonwoven fabric was manufactured in the same manner as in Example 6, except that the basis weight was changed from 100 g / m ² to 40 g / m ² . Table 1 shows the evaluation results of the obtained nonwoven fabric.

TPU-4 and a propylene homopolymer having an MFR (measured at a temperature of 230 ° C. and a load of 2.16 kg according to ASTM D1238 at a temperature of 230 ° C.) of 60 g / 10 minutes, a density of 0.91 g / cm ³ and a melting point of 160 ° C. (hereinafter referred to as “PP- 1 ") in a weight ratio of 50/50, and a spunbond nonwoven fabric was produced in the same manner as in Example 1 except that a spunbond molding machine equipped with a die having a hollow eight-piece nozzle was used. did. Table 1 shows the evaluation results of the obtained nonwoven fabric.

[Comparative Example 1]
Thermoplastic polyurethane elastomer having a solidification start temperature of 60.2 ° C., a number of particles of a polar solvent-insoluble component of 1.4 million / g, and a hardness of 75A (manufactured by BASF Japan K.K., trade name: Elasttran XET-275-10MS) Was previously dried at 100 ° C. for 8 hours using a drier to adjust the water content to 89 ppm.

  A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1, except that this XET-275-10MS was used instead of TPU-1. In this production, the fibers were fused to the spinning tower, resulting in poor spinnability. Further, during the hot embossing, a part of the nonwoven fabric adhered to the embossing roll. Table 2 shows the evaluation results of the obtained nonwoven fabric.

[Comparative Example 2]
A solidification start temperature of 78.4 ° C, a number of particles of a polar solvent-insoluble component of 3.2 million particles / g, and a hardness of 82A are thermoplastic polyurethane elastomers (manufactured by BASF Japan Ltd., trade name: Elastollan 1180A-10). It was previously dried at 100 ° C. for 8 hours using a dryer, and the moisture value was adjusted to 115 ppm.

  A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that this 1180A-10 was used instead of TPU-1. When the fiber was spun so as to have a fiber diameter of 50 μm or less, a large number of yarn breaks occurred in the spinning tower, and a nonwoven fabric was not obtained. Therefore, spun at a fiber diameter such that a nonwoven fabric was obtained, and a spunbonded nonwoven fabric was manufactured. However, even in this nonwoven fabric, broken fibers were mixed, and the touch feeling was poor. Table 2 shows the evaluation results of the obtained nonwoven fabric.

[Comparative Example 3]
A thermoplastic polyurethane elastomer (manufactured by BASF Japan K.K., trade name: Elastollan ET-385) having a solidification start temperature of 86.9 ° C., a number of particles of a polar solvent-insoluble component of 2.8 million / g, and a hardness of 84A, It was previously dried at 100 ° C. for 8 hours using a dryer, and the water value was set to 89 ppm.

Using ET-385 instead of TPU-1, fibers were produced using a melt blown molding machine under the conditions of a die temperature of 230 ° C. and a single hole discharge rate of 2.0 g / (minute / hole), and the fibers were formed on the collecting surface. Deposited. The fibers were self-fused by the heat of the fibers to produce a melt-blown nonwoven fabric having a basis weight of 100 g / m ² .

  Although the fiber diameter of the obtained nonwoven fabric was small, the fiber diameter distribution was wide and the feel was poor. Table 2 shows the evaluation results of the obtained nonwoven fabric.

[Comparative Example 4]
A spunbonded nonwoven fabric was manufactured in the same manner as in Example 1 except that TPU-3 was used instead of TPU-1. However, if the fiber is spun to a fiber diameter of 50 μm or less, many yarn breaks occur in the spinning tower, and winding around the emboss roller occurred during embossing, so that a nonwoven fabric was not obtained. could not. Table 2 shows other evaluation results.

MFR (measured at 230 ° C. under a load of 2.16 kg according to ASTM D1238) 15 g / 10 min, density 0.91 g / cm ³ , propylene homopolymer having a melting point of 160 ° C. (hereinafter abbreviated as “PP-2”) Is used as a core, and PP-1 is used as a sheath, and a coaxial core-sheath composite melt spinning having a core / sheath weight ratio of 10/90 is performed by a spun bond method so that a basis weight is 20 g / m ^2. (Hereinafter referred to as “Web-1”) was deposited on the collecting surface.

Next, a web made of TPU-4 (hereinafter, referred to as “web-2”) was deposited so that the basis weight was 40 g / m ² , in the same manner as in Example 6, except that the web was deposited on the web-1. I let it. Thereafter, in the same manner as described above, the web (hereinafter, referred to as “Web-3”) made of the core-sheath composite fiber containing PP-1 and PP-2 is adjusted to have a basis weight of 20 g / m ^2. 2 was deposited.

The deposit consisting of these three layers is embossed at 100 ° C. (emboss area ratio: 7%, emboss roll diameter: 150 mmφ, stamp pitch: 2.1 mm in longitudinal and transverse directions, stamp shape: rhombus), and extensible nonwoven fabric A spunbonded nonwoven fabric laminate having a basis weight of 80 g / m ² , comprising a layer, a stretchable nonwoven fabric layer, and an extensible nonwoven fabric layer, was produced.

Table 3 shows the evaluation results of the obtained laminate. Here, the “tensile strength (first time)” is the tensile strength at the time of 100% elongation in the first tensile test. The term “tensile strength (second time)” means that the test piece recovered to its original length in the first tensile test was stretched again under the same conditions (1).
(At the time of 00% elongation).

  The stretchable nonwoven fabric according to the present invention has high elasticity, low residual strain, and flexibility, has a narrow fiber diameter distribution, and has an excellent tactile sensation, and is used as a sanitary material, an industrial material, clothing, and a sports material. be able to.

Claims (6)

A spunbonded stretchable nonwoven made of fibers formed from a polymer including a thermoplastic polyurethane elastomer,
The thermoplastic polyurethane elastomer has a solidification start temperature of at least 65 ° C. measured by a differential scanning calorimeter (DSC), and is measured by attaching a 100 μm aperture to a particle size distribution analyzer based on a pore electric resistance method. The number of particles of the polar solvent-insoluble component is 3,000,000 / g or less;
The fiber has a value (Sn / Sn) obtained by dividing the standard deviation (Sn) of the fiber diameter by the average fiber diameter (X _ave ).
_Xave ) is 0.15 or less.   The stretchable nonwoven fabric according to claim 1, wherein the polymer contains the thermoplastic polyurethane elastomer in an amount of 10% by weight or more. The thermoplastic polyurethane elastomer,
The sum (a) of the heat of fusion determined from the endothermic peak having a peak temperature in the range of 90 ° C. or more and 140 ° C. or less measured by a differential scanning calorimeter (DSC), and the peak temperature exceeding 140 ° C. and 220 ° C. or less The sum (b) of the heat of fusion determined from the endothermic peak in the range of
a / (a + b) × 100 ≦ 80 (1)
The elastic nonwoven fabric according to claim 1 or 2, wherein the following relationship is satisfied.   A sanitary material comprising the stretchable nonwoven fabric according to claim 1. A method for producing a stretchable nonwoven fabric comprising fibers formed from a polymer containing a thermoplastic polyurethane elastomer by spunbond molding a polymer,
The thermoplastic polyurethane elastomer has a solidification start temperature of at least 65 ° C. measured by a differential scanning calorimeter (DSC), and is measured by attaching a 100 μm aperture to a particle size distribution analyzer based on a pore electric resistance method. The number of particles of the polar solvent-insoluble component is 3,000,000 / g or less;
The fiber has a value (Sn / Sn) obtained by dividing the standard deviation (Sn) of the fiber diameter by the average fiber diameter (X _ave ).
_Xave ) is 0.15 or less. Particles having a solidification onset temperature of 65 ° C. or higher measured by a differential scanning calorimeter (DSC) and a polar solvent-insoluble component measured by attaching a 100 μm aperture to a particle size distribution analyzer based on a pore electric resistance method. The number is 3 million / g or less,
It is possible to produce a spunbonded stretchable nonwoven fabric having a value (Sn / X _ave ) obtained by dividing the standard deviation (Sn) of the fiber diameter by the average fiber diameter (X _ave ) of 0.15 or less. Characteristic thermoplastic polyurethane elastomer for spun bond molding.