WO2021200371A1

WO2021200371A1 - Spun-bonded non-woven cloth

Info

Publication number: WO2021200371A1
Application number: PCT/JP2021/011886
Authority: WO
Inventors: 竹光洋樹; 山中崇弘; 小出現
Original assignee: 東レ株式会社
Priority date: 2020-03-31
Filing date: 2021-03-23
Publication date: 2021-10-07
Also published as: TW202142756A; JPWO2021200371A1

Abstract

The purpose of the present invention is to provide a non-woven cloth in which spinning properties and heat-fusing properties are both excellent, and which has superior production stability and superior texture.　To achieve this purpose, this spun-bonded non-woven cloth is configured from fibers including a polyethylene polymer, the polyethylene polymer being a copolymer of ethylene and a C3-5 α-olefin, the α-olefin content of the polymer component in the polyethylene polymer being 0.10-5.0 mol%, and the compression rate of the non-woven cloth being 8-19%.

Description

Spun bond non-woven fabric

The present invention relates to a spunbonded non-woven fabric.

Spunbond unemployed cloth made of polyolefin, especially polypropylene spunbond unemployed cloth, is widely used mainly for sanitary materials because it is low cost and has excellent flexibility.

Many studies have been conducted on the technology to further enhance the flexibility, which is a feature of polyolefin spunbonded non-woven fabrics. Among them, the use of polyethylene, which has a lower elastic modulus than polypropylene, has been studied.

The problems with spunbonded non-woven fabrics using polyethylene are that polyethylene has poor spinnability and is prone to thread breakage, resulting in many sheet defects. If it is strong, the texture will deteriorate.

Regarding the technique for obtaining a non-woven fabric containing a polyethylene-based polymer having improved spinnability and a good texture, the sheath component of the composite fiber contains substantially 1 to 10% by mass of 1-octene as a copolymer of ethylene and 1-octene. It is disclosed that a linear low-density polyethylene having a density of 0.900 to 0.940 g / cm ³ , a melt index value of 5 to 45 g / 10 minutes, and a heat of fusion of 25 cal / g or more is used. (See Patent Document 1).

Further, a polyethylene composition containing 100% by weight or less of ethylene-derived units and less than 20% by weight of 1 or more α-olefin comonomer-derived units, wherein the density of the polyethylene composition is 0.920 to 0.970 g. in the range of / cm ^3, a molecular weight distribution (Mw / Mn) in the range is 1.70 to 3.5 in the range melt index value is 0.2 ~ 1000 g / 10 min, a molecular weight distribution (Mz / The spinnability is improved by using a polyethylene composition in which Mw) is in the range of less than 2.5 and the vinyl unsaturatedity is less than 0.1 vinyl per 1000 carbon atoms present in the main chain of the composition. (See Patent Document 2).

Special Fair 07-103507 Gazette Japanese Patent Publication No. 2011-527723

However, although Patent Document 1 describes that the frequency of yarn breakage is low, the single yarn fineness reached in the examples is 3.0 denier (estimated average single fiber diameter 21.3 μm), which is suitable for sanitary materials. As a spunbonded non-woven fabric, the fiber diameter is large and the texture is inferior. In Patent Document 1, fibers of 3.0 denier or less have not been obtained, and it cannot be said that the spinnability is satisfactory as a non-woven fabric for sanitary materials. Further, the heat treatment temperature (heat adhesion temperature) of the non-woven fabric is in the range of 90 to 110 ° C. However, since the heat adhesion is usually weak in the above temperature range, fluffing is likely to occur, and the problem of heat adhesion can be solved. No.

Further, in Patent Document 2, the single yarn fineness reached in the examples is 3.0 denier, which is a large fiber diameter and inferior in texture as a spunbonded non-woven fabric for sanitary materials. In Patent Document 2, fibers of 3.0 denier or less have not been obtained, and it cannot be said that the spinnability is satisfactory as a non-woven fabric for sanitary materials.

Therefore, an object of the present invention is to provide a non-woven fabric having good spinnability / thermal adhesiveness, excellent production stability, and excellent texture in view of the above problems.

The spunbonded non-woven fabric of the present invention is composed of fibers containing a polyethylene-based polymer, and the polyethylene-based polymer is a copolymer of ethylene and an α-olefin having 3 to 5 carbon atoms, and is a polymerization component of the polyethylene-based polymer. The content of α-olefin in the above is 0.10 to 5.0 mol%, and the pressure-bonding ratio of the non-woven fabric is 8 to 19%.

According to a preferred embodiment of the spunbonded nonwoven fabric of the present invention, the α-olefin is 1-butene.

According to a preferred embodiment of the spunbonded nonwoven fabric of the present invention, the content of α-olefin is 0.10 to 3.0 mol%.

According to a preferred embodiment of the spunbonded nonwoven fabric of the present invention, the pressure-bonding ratio of the nonwoven fabric is 8 to 14%.

According to the present invention, it is possible to provide a non-woven fabric having good spinnability / thermal adhesiveness, excellent production stability, and excellent texture.

By doing so, it is possible to obtain a non-woven fabric having good spinnability / thermal adhesiveness, excellent production stability, and excellent texture. In the present invention, excellent production stability means that both spinnability and thermal adhesion are good.

The details will be explained below.

[Polyethylene polymer]
The polyethylene-based polymer used in the present invention is a copolymer of ethylene and an α-olefin having 3 to 5 carbon atoms, and more preferably a copolymer of ethylene and 1-butene.
When the number of carbon atoms of the α-olefin is 6 or more, the molecular chains are liable to be entangled at the time of melting, which leads to the occurrence of thread breakage. Further, since the length of the side chain becomes long, the crystallinity of the polyethylene-based polymer is lowered, and the non-woven fabric has a texture inferior to the silky feel of the fiber surface. Furthermore, since the amount of amorphous components having a low melting point increases, it becomes easier to wrap around the roll during thermal bonding, so that thermal bonding cannot be performed at a temperature that can suppress fluffing of the non-woven fabric, and it cannot be used as a sanitary material. Will be.

The content of α-olefin in the polymerization component of the polyethylene-based polymer used in the present invention is 0.10 to 5.0 mol% or less, preferably 0.10 to 4.0 mol, in the polyethylene-based polymer. % Or less, more preferably 0.10 to 3.0 mol% or less. When the content of α-olefin is more than 5.0 mol%, there are many side chain branches, and the molecular chains are liable to be entangled at the time of melting, which leads to the occurrence of yarn breakage. In addition, since the crystallinity decreases and the amorphous component having a low melting point increases, it becomes easy to wrap around the roll during thermal adhesion, so that thermal adhesion cannot be performed at a temperature at which fluffing of the non-woven fabric can be suppressed. It cannot be used as a sanitary material. Further, the crystallinity is lowered, so that the non-woven fabric has a texture inferior to the silky feel of the fiber surface. On the other hand, if the content of the α-olefin is less than 0.10 mol%, the crystallinity becomes too high, and the non-woven fabric has a hard texture and cannot be used as a sanitary material. In addition, crystallization is extremely easy to proceed during spinning, which makes it difficult for the yarn to be thinned, which leads to yarn breakage when trying to obtain fine fibers that are flexible and have excellent uniformity.

The α-olefin species and α-olefin contents in the polymerization component of the polyethylene-based polymer can be calculated, for example, from the peak position and peak area ratio detected by a nuclear magnetic resonance apparatus (NMR).

The density of the polyethylene-based polymer used in the present invention ^{is preferably 0.935 to 0.965 g / cm 3} , and more preferably 0.945 to 0.965 g / cm ³ . When the density is 0.935 g / cm ³ or more, since there are few amorphous components having a low melting point, it becomes difficult to wrap around the roll during heat bonding. Therefore, it becomes easy to perform thermal adhesion at a temperature at which fluffing of the non-woven fabric can be suppressed, and it tends to be suitable for use as a sanitary material. Further, by increasing the crystallinity, it becomes easy to obtain a non-woven fabric having a texture having a sufficient smooth feeling on the fiber surface. On the other hand, when the density is 0.965 g / cm ³ or less, the crystallinity is unlikely to be too high, and a non-woven fabric having a soft texture is likely to be obtained, so that a material suitable as a sanitary material can be easily obtained.

The ethylene component of the polyethylene-based polymer used in the present invention is not particularly limited, but for example, (1) petroleum-derived ethylene obtained by high-temperature thermal decomposition of naphtha, (2) vegetable ethanol obtained from sugar cane and the like are compared. Examples thereof include biobase-derived ethylene obtained by dehydration at a low temperature. Of these, the bio-based ethylene of (2) is preferable because of the growing interest in environmental consideration in the market in recent years.

When polyethylene containing biobase-derived ethylene as an ethylene component is used, the proportion of biobase-derived carbon atoms in the non-woven fabric is preferably 20% or more. If it is 20% or more, the _{amount of CO 2} reduction will be large and the contribution to the environment will be large.

The proportion of carbon atoms derived from the biobase is measured based on the ASTM D6866 method. In the ASTM D6866 method, it is possible to know from the amount of radioisotope of a carbon atom whether the component is derived from a biobase or a petroleum-derived resource. If all the carbon atoms are derived from the biobase, the ratio of carbon atoms derived from the biobase is 100%.

The melting point of the polyethylene-based polymer used in the present invention is preferably 60 to 180 ° C, more preferably 80 to 160 ° C, and even more preferably 100 to 140 ° C. By setting the melting point to preferably 60 ° C. or higher, more preferably 80 ° C. or higher, and further preferably 100 ° C. or higher, it becomes easy to obtain heat resistance that can withstand practical use. Further, by setting the melting point to preferably 180 ° C. or lower, more preferably 160 ° C. or lower, and further preferably 140 ° C. or lower, it becomes easier to cool the yarn discharged from the mouthpiece, and fusion between fibers is suppressed and stable. It becomes easier to spin the yarn.

The polyethylene-based polymer used in the present invention may be a mixture of two or more types of polyethylene-based polymers.

The fibers used in the spunbonded nonwoven fabric of the present invention may further contain other olefin resins, thermoplastic elastomers, etc. in addition to the polyethylene copolymer. Above all, from the viewpoint of imparting flexibility, it is preferable to contain a low crystallinity polyethylene-based elastomer. When other olefin-based resin, thermoplastic elastomer, etc. are contained, the content is preferably 20% by mass or less, more preferably 15% by mass, in 100% by mass of the fiber in order to fully express the characteristics of the polyethylene-based polymer. It is as follows. Further, in order to fully exert the effect of imparting flexibility, the content is preferably 5% by mass or more.

The polyethylene-based polymer used in the present invention includes antioxidants, weather stabilizers, light-resistant stabilizers, antistatic agents, antifoaming agents, antiblocking agents, lubricants, and nucleating agents as long as the effects of the present invention are not impaired. , Additives such as pigments, and other polymers can be added as needed.

The melt flow rate of the polyethylene-based polymer used in the present invention (hereinafter, may be referred to as MFR) is preferably 5 to 150 g / 10 minutes, more preferably 10 to 120 g / 10 minutes, still more preferably. Is 10 to 100 g / 10 minutes. When the MFR is 10 g / 10 minutes or more, the viscosity at the time of melting becomes low, and the followability to thinning at the time of spinning is improved, so that yarn breakage is less likely to occur and stable production is facilitated. On the other hand, when the MFR is 150 g / 10 minutes or less, the molecular weight is large and the strength of the fiber is high, so that it is easy to have a strength that can withstand practical use. The MFR of the polyethylene-based polymer refers to a value measured at a temperature of 190 ° C. and a load of 2.16 kg in accordance with ASTM D1238.

The polyethylene-based polymer may be, for example, a polymer synthesized by a general Chigra natta catalyst, or a polymer synthesized by a single-site active catalyst typified by metallocene.

[Fiber containing polyethylene polymer]
The fibers containing the polyethylene-based polymer constituting the spunbonded nonwoven fabric of the present invention preferably have an average single fiber diameter of 6.5 to 19.5 μm. By setting the average single fiber diameter to 6.5 μm or more, preferably 7.5 μm or more, and more preferably 8.5 μm or more, deterioration of spinnability is prevented, and a stable and high-quality spunbonded non-woven fabric is produced. It will be easier. On the other hand, by setting the average single fiber diameter to 19.5 μm or less, preferably 19.0 μm or less, and more preferably 18.5 μm or less, a spunbonded nonwoven fabric having improved flexibility and high uniformity can be obtained. It will be easier.

The fiber containing the polyethylene-based polymer described above preferably has a single fiber diameter CV value of 7% or less. By setting the CV value of the single fiber diameter to preferably 7% or less, more preferably 6% or less, and further preferably 5% or less, it is possible to prevent the surface from becoming rough and to have a highly uniform spunbonded non-woven fabric. Is easy to obtain. The CV value of the single fiber diameter is dominated by the back pressure of the spinneret, the yarn cooling condition, and the uniformity of the drawing condition, and can be controlled by appropriately adjusting these.

Further, as the fiber containing the polyethylene-based polymer described above, a composite fiber in which the polyethylene-based polymer is combined with at least one polyolefin-based resin or polyester-based resin can be used. Examples of the composite form of the composite fiber include composite forms such as a concentric sheath type, an eccentric sheath type, and a sea island type. Above all, it is preferable to use a concentric sheath type composite form because it has excellent spinnability and fibers can be uniformly bonded to each other by heat bonding.

As the olefin-based monomer for obtaining a polyolefin-based resin other than the polyethylene-based polymer used in the case of forming a composite fiber, those having 3 to 10 carbon atoms are preferably used, and specifically, propylene and 1-butene. , 1-Pentene, 1-Hexane, 4-Methyl-1-pentene, 1-octene and the like. These can be used alone or in combination of two or more. Among them, polypropylene is preferably used from the viewpoint of strength and flexibility of the non-woven fabric, and a copolymer of polypropylene and another α-olefin is also preferably used.

When polypropylene is used as the above-mentioned polyolefin resin, it is preferable to use homopolypropylene from the viewpoint of strength when the spunbonded non-woven fabric is used as a non-woven fabric for sanitary materials.

On the other hand, examples of the polyester-based resin include polyethylene terephthalate, polybutylene terephthalate, polylactic acid, and copolymers with these resins.

The MFR of polypropylene is preferably 1 to 1000 g / 10 minutes, more preferably 10 to 500 g / 10 minutes, and even more preferably 20 to 250 g / 10 minutes. By setting the MFR in the range of 1 to 1000 g / 10 minutes, stable spinning is facilitated, orientation crystallization is facilitated, and high-strength fibers are easily obtained. The polypropylene MFR refers to a value measured at a temperature of 230 ° C. and a load of 2.16 kg in accordance with ASTM D-1238.

Polypropylene may be a polymer synthesized by a general Chigra natta catalyst, or may be a polymer synthesized by a single-site active catalyst typified by metallocene.

When used as a composite fiber, the mass ratio of the polyethylene polymer to the other polyolefin resin or polyester resin is preferably 90/10 to 10/90. By setting the mass ratio of the polyethylene-based polymer to 10% by mass or more, sufficient flexibility / thermal adhesiveness can be easily obtained. By setting the mass ratio of the polyolefin resin to 10% by mass or more, it becomes easy to obtain sufficient strength for use as a non-woven fabric for sanitary materials.

The fiber containing the polyethylene polymer constituting the spunbonded nonwoven fabric of the present invention may contain a fatty acid amide compound having 23 or more and 50 or less carbon atoms in order to improve slipperiness and flexibility.

The rate of movement of the fatty acid amide compound to the fiber surface can be adjusted by the number of carbon atoms of the fatty acid amide compound contained in the fiber containing the polyethylene polymer. By setting the number of carbon atoms of the fatty acid amide compound to preferably 23 or more, and more preferably 30 or more, the fatty acid amide compound is suppressed from being excessively exposed on the fiber surface, and the spinnability and processing stability are excellent. , It becomes easy to maintain high productivity. On the other hand, when the number of carbon atoms of the fatty acid amide compound is preferably 50 or less, more preferably 42 or less, the fatty acid amide compound can easily move to the fiber surface, and the spunbonded nonwoven fabric can be easily provided with slipperiness and flexibility. Become.

Examples of fatty acid amide compounds having 23 or more and 50 or less carbon atoms include saturated fatty acid monoamide compounds, saturated fatty acid diamide compounds, unsaturated fatty acid monoamide compounds, and unsaturated fatty acid diamide compounds.

Specifically, as fatty acid amide compounds having 23 or more and 50 or less carbon atoms, tetradocosanoic acid amide, hexadokosanoic acid amide, octadokosanic acid amide, nervonic acid amide, tetracosaentapenic acid amide, heric acid amide, ethylenebislauric acid amide, Methylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbechenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisstearic acid amide, hexamethylene hydroxystearic acid amide, distearyl adipic acid Examples thereof include amides, distearyl sebacic acid amides, ethylene bisoleic acid amides, ethylene biserucic acid amides, and hexamethylene bisoleic acid amides, and these can be used in combination of two or more.

Among them, ethylene bisstearic acid amide is particularly preferable. Since ethylene bisstearic acid amide has excellent thermal stability, thermal decomposition is unlikely to occur even if melt spinning is performed. Therefore, by using a polyethylene-based copolymer containing an ethylene bisstearic acid amide, it becomes easy to obtain a spunbonded nonwoven fabric having excellent slipperiness and flexibility while maintaining high productivity.

The content of the fatty acid amide compound in the fiber containing the polyethylene-based polymer is preferably 0.01 to 5.0% by mass. By setting the content of the fatty acid amide compound to preferably 0.01 to 5.0% by mass, more preferably 0.1 to 3.0% by mass, and further preferably 0.1 to 1.0% by mass. , Appropriate slipperiness and flexibility can be imparted while maintaining spinnability.

The content referred to here is the mass of the fatty acid amide compound contained in the fiber containing the polyethylene-based polymer constituting the spunbonded nonwoven fabric of the present invention, specifically, the entire resin constituting the fiber containing the polyethylene-based polymer. Say a percentage. For example, even when the fatty acid amide compound is added only to the sheath portion component constituting the core-sheath type composite fiber, the content ratio to the total amount of the core-sheath component is calculated.

[Spanbond non-woven fabric]
The MFR of the spunbonded non-woven fabric of the present invention is preferably 5 to 150 g / 10 minutes or less, which is the same as the reason in the range of MFR of the polyethylene-based polymer described above. The MFR is more preferably 10 g / min or more, still more preferably 15 g / 10 min or more, and more preferably 120 g / 10 min or less, still more preferably 100 g / 10 min or less.

The MFR of the spunbonded non-woven fabric is measured based on ASTM D-1238 (method A) under the conditions of a load of 2.16 kg and a temperature of 190 ° C.

The apparent density of the spunbonded nonwoven fabric of the present invention is preferably ^{0.05 to 0.35 g / cm 3.} By setting the apparent density to preferably 0.35 g / cm ³ or less, more preferably 0.30 g / cm ³ or less, and further preferably 0.25 g / cm ³ or less, the fibers are tightly packed and spunbonded. The flexibility of the non-woven fabric is less likely to be impaired. On the other hand, an apparent density preferably between 0.05 g / cm ³ or more, more preferably set to 0.08 g / cm ³ or more, more preferably by a 0.10 g / cm ³ or more, the generation of fuzz or delamination It becomes easy to obtain a spunbonded non-woven fabric having mechanical strength and handleability that can be suppressed and can withstand practical use.

The basis weight of the spunbonded nonwoven fabric of the present invention is preferably ^{10 to 100 g / m 2.} By setting the basis weight to preferably 10 g / m ² or more, more preferably 13 g / m ² or more, and further preferably 15 g / m ² or more, it becomes easy to obtain a spunbonded non-woven fabric having mechanical strength that can be put into practical use. .. On the other hand, by setting the basis weight to preferably 100 g / m ² or less, more preferably 50 g / m ² or less, and further preferably 30 g / m ² or less, appropriate flexibility suitable for use as a non-woven fabric for sanitary materials can be obtained. It becomes easy to obtain the spunbonded non-woven fabric to have.

The thickness of the spunbonded nonwoven fabric of the present invention is preferably 0.05 to 1.5 mm. By setting the thickness to preferably 0.05 to 1.5 mm, more preferably 0.08 to 1.0 mm, still more preferably 0.10 to 0.8 mm, flexibility and appropriate cushioning properties are provided, and hygiene is provided. As the spunbonded non-woven fabric for materials, it can be a spunbonded non-woven fabric particularly suitable for use in disposable diaper applications.

The fluff grade of the spunbonded non-woven fabric of the present invention is preferably 3.0 grade or higher. When the fluff grade is 3.0 grade or higher, pilling or breakage of the non-woven fabric is unlikely to occur, so that the material can be suitably used as a sanitary material. Furthermore, since it is sufficiently adhered, even slight fluffing is unlikely to occur, and it is easy to obtain a non-woven fabric having an excellent surface smoothness.

The average flexural rigidity B of the spunbonded non-woven fabric of the present invention by the KES method (KAWABATA EVALUATION SYSTEM) is preferably 0.001 gf · cm ² / cm or more and 0.03 gf · cm ² / cm or less. By setting the average flexural rigidity B by the KES method to preferably 0.02 gf · cm ² / cm or less, more preferably 0.017 gf · cm ² / cm or less, and further preferably 0.015 gf · cm ² / cm or less. In particular, when used as a spunbonded non-woven fabric for sanitary materials, sufficient flexibility can be easily obtained. Further, when the average bending rigidity B by the KES method is extremely low, the handleability may be inferior. Therefore, the average bending rigidity B is preferably 0.001 gf · cm ² / cm or more. The average flexural rigidity B according to the KES method can be adjusted by the basis weight, single fiber diameter, and thermocompression bonding conditions (compression rate, temperature, and linear pressure).

The coefficient of friction MIU of the spunbonded non-woven fabric of the present invention is preferably 0.2 or less, more preferably 0.15 or less, and even more preferably 0.13 or less. By setting the friction coefficient MIU in such a range, the slipperiness of the surface of the non-woven fabric is likely to be improved, and the spunbonded non-woven fabric having a better feel to the touch can be obtained. On the other hand, the coefficient of friction MIU is preferably 0.05 or more, more preferably 0.08 or more, and further preferably 0.1 or more. By setting the coefficient of friction MIU to such a range, it is possible to prevent the spunability from being deteriorated due to excessive addition of a lubricant, and the yarns from slipping and the texture to be deteriorated when the yarns are collected on the net. It will be easier. The coefficient of friction MIU by the KES method can be controlled by adjusting the average single fiber diameter, the fiber dispersity, the crystallinity of the polyolefin resin, and the like, or by adding a lubricant to the polyolefin resin.

[Manufacturing method of spunbonded non-woven fabric]
Next, a preferred embodiment of the method for producing the spunbonded nonwoven fabric of the present invention will be specifically described.

The spunbonded non-woven fabric of the present invention is a long-fiber non-woven fabric manufactured by the spunbond (S) method. As a method for producing a non-woven fabric, a spunbond method, a flash spinning method, a wet method, a card method, an airlaid method and the like can be generally mentioned, but the spunbond method is excellent in productivity and mechanical strength and is short. It is possible to suppress fluffing and fiber shedding that are likely to occur with fibrous non-woven fabrics. Further, it is preferable to laminate a plurality of layers of the spunbond (S) non-woven fabric layer with SS, SSS and SSSS because productivity and formation uniformity are improved.

In the spunbond method, first, the molten thermoplastic resin is spun from the spinneret as long fibers, which is suction-stretched with compressed air by an ejector, and then the fibers are collected on a moving net to form a non-woven fiber web. .. Further, the obtained non-woven fiber web is heat-bonded to obtain a spunbonded non-woven fabric.

As the shape of the spinneret and the ejector, various shapes such as a round shape and a rectangular shape can be adopted. Among them, the combination of a rectangular base and a rectangular ejector is possible because the amount of compressed air used is relatively small and the energy cost is excellent, the threads are less likely to be fused or scratched, and the threads can be easily opened. It is preferably used.

In the present invention, the polyethylene-based polymer is melted in an extruder, weighed and supplied to a spinneret, and spun as long fibers. The spinning temperature when the polyethylene-based polymer is melted and spun is preferably 180 to 270 ° C, more preferably 190 to 260 ° C, and even more preferably 200 to 250 ° C. By setting the spinning temperature within the above range, a stable molten state can be obtained and more excellent spinning properties can be obtained.

The spun long fiber yarn is then cooled. Examples of the method of cooling the spun yarn include a method of forcibly blowing cold air on the yarn, a method of naturally cooling at the atmospheric temperature around the yarn, and a method of adjusting the distance between the spinneret and the ejector. Etc., or a method of combining these methods can be adopted. Further, the cooling conditions can be appropriately adjusted and adopted in consideration of the discharge amount per single hole of the spinneret, the spinning temperature, the atmospheric temperature and the like.

Next, the cooled and solidified yarn is towed and stretched by the compressed air injected from the ejector.

The spinning speed is preferably 1500 to 6500 m / min, more preferably 2000 to 6500 m / min, and even more preferably 2500 to 6500 m / min. By setting the spinning speed to 1500 to 6500 m / min, high productivity can be obtained, orientation and crystallization of fibers can be advanced, and long fibers having high mechanical strength can be obtained.

Subsequently, the obtained long fibers are collected on a moving net and made into a non-woven fiber web.

In the present invention, it is also preferable to temporarily bond the non-woven fiber web with a thermal flat roll from one side of the net. By doing so, it is possible to prevent the surface layer of the non-woven fiber web from being turned over or blown off during transportation on the net, resulting in deterioration of the texture, and from collecting the threads to thermocompression bonding. Transportability can be improved.

Subsequently, the intended non-woven fabric can be obtained by integrating the obtained non-woven fiber webs by heat bonding.

As a method of integrating the non-woven fiber web by heat bonding, a heat embossed roll in which the upper and lower roll surfaces are engraved (concavo-convex parts), one roll has a flat (smooth) surface, and the other roll has a flat surface. Thermal bonding methods using various rolls, such as thermal embossing rolls consisting of rolls with engraved surfaces (uneven parts) and thermal calendar rolls consisting of a pair of upper and lower flat (smooth) rolls, and horns Examples thereof include a method such as ultrasonic bonding in which heat welding is performed by ultrasonic vibration. Among them, it is highly productive, mechanical strength is given by the partial heat-bonded part, and the texture and touch unique to non-woven fabric can be maintained by the non-bonded part. Use a heat embossed roll with uneven parts) or a combination of a roll with a flat (smooth) surface on one roll and a roll with engraving (uneven parts) on the surface of the other roll. Is preferable.

As the surface material of the heat embossed roll, a sufficient thermocompression bonding effect can be easily obtained, and the engraving (concavo-convex part) of one embossed roll is difficult to be transferred to the surface of the other roll. Is preferable.

The pressure-bonding ratio of the spunbonded nonwoven fabric of the present invention is 8 to 19%, preferably 8 to 16%, and more preferably 8 to 14%. If the pressure-bonding ratio exceeds 19%, thermal adhesion becomes excessive, and in thermal adhesion of fibers made of ethylene-based polymers having a low melting point, wrapping around embossed rolls frequently occurs, making stable fabric production difficult. Furthermore, due to excessive adhesion, the texture becomes hard and unsuitable as a sanitary material. On the other hand, when the pressure-bonding ratio is less than 8%, the thermal adhesion is weak, the mechanical strength that can be practically used as a spunbonded non-woven fabric cannot be obtained, and the fluff is easily fluffed, which makes it unsuitable for use as a sanitary material. It ends up.

The crimping ratio here means the area ratio of the adhesive part to the entire spunbonded non-woven fabric. Specifically, when heat-bonding with a pair of uneven rolls, the spunbonded non-woven fabric of the portion (adhesive portion) where the convex portion of the upper roll and the convex portion of the lower roll overlap and come into contact with the non-woven fiber web. It refers to the ratio to the whole. Further, in the case of heat-bonding between a roll having irregularities and a flat roll, it means the ratio of the convex portion of the roll having irregularities to the entire spunbonded non-woven fabric of the portion (adhesive portion) in contact with the non-woven fiber web. Further, in the case of ultrasonic bonding, it refers to the ratio of the portion (adhesive portion) to be heat-welded by ultrasonic processing to the entire spunbonded non-woven fabric.

As a method of setting the pressure-bonding ratio of the spunbonded nonwoven fabric of the present invention within the above range, for example, when heat-bonding is performed by a roll having a pair of irregularities, the convex portion of the upper roll and the convex portion of the lower roll do not overlap each other. Examples thereof include a method of adjusting the area of the portion that comes into contact with the woven fiber web, and a method of adjusting the area of the convex portion of the roll having unevenness in the case of heat-bonding the roll having unevenness with a flat roll.

As the shape of the bonded portion by thermal embossing roll or ultrasonic bonding, a circular shape, an elliptical shape, a square shape, a rectangular shape, a parallelogram, a rhombus shape, a regular hexagonal shape, a regular octagonal shape, or the like can be used. Further, it is preferable that the adhesive portions are uniformly present at regular intervals in the longitudinal direction (conveyance direction) and the width direction of the spunbonded nonwoven fabric. By doing so, it is possible to reduce variations in the mechanical strength of the spunbonded non-woven fabric.

The linear pressure of the heat embossing roll at the time of heat bonding is preferably 50 to 500 N / cm. By setting the linear pressure of the roll to preferably 50 N / cm or more, more preferably 100 N / cm or more, and further preferably 150 N / cm or more, a spunbonded non-woven fabric having mechanical strength that can be appropriately heat-bonded and put into practical use. Is easy to obtain. On the other hand, by setting the linear pressure of the heat embossed roll to preferably 500 N / cm or less, more preferably 400 N / cm or less, and further preferably 300 N / cm or less, it is used as a spunbonded non-woven fabric for sanitary materials, especially for disposable diapers. It is possible to obtain an appropriate degree of flexibility suitable for use in.

Further, in the present invention, for the purpose of adjusting the thickness of the spunbonded nonwoven fabric, thermocompression bonding may be performed by a thermal calendar roll composed of a pair of upper and lower flat rolls before and / or after thermal bonding by the above thermal embossing roll. can. A pair of upper and lower flat rolls is a metal roll or an elastic roll having no unevenness on the surface of the roll, and a metal roll and a metal roll may be paired, or a metal roll and an elastic roll may be paired. Can be used. Further, the elastic roll here is a roll made of a material having elasticity as compared with a metal roll. Examples of the elastic roll include so-called paper rolls such as paper, cotton and aramid paper, and resin rolls made of urethane-based resin, epoxy-based resin, silicon-based resin, polyester-based resin and hard rubber, and a mixture thereof. Be done.

The spunbonded non-woven fabric of the present invention has high productivity, flexibility, and excellent surface texture of the non-woven fabric, and can be suitably used for sanitary material applications such as disposable disposable diapers and napkins. Among the sanitary materials, it can be particularly preferably used for the back sheet of disposable diapers.

Next, the non-woven fabric of the present invention and the method for producing the same will be specifically described based on Examples, but the present invention is not limited thereto.

(Evaluation method)
(1) Spinnability The number of yarn breaks per ton of production was counted and judged according to the following criteria. The judgments of A and B were passed, and the judgments of C and D were rejected.
A: The number of thread breaks is 0.5 times / ton or less.
B: The number of thread breaks is more than 0.5 times / ton and 2.0 times / ton or less.
C: The number of thread breaks is more than 2.0 times / ton and 5.0 times / ton or less.
D: The number of thread breaks is more than 5.0 times / ton.

(2) Heat Adhesive The sheet state of the embossed roll was observed, and the sheet was taken on the embossed roll when the temperature was raised to a temperature at which the sheet did not fluff, and the judgment was made according to the following criteria. The judgments of A and B were passed, and the judgments of C and D were rejected.
A: There is no sheet to emboss.
B: There is a sheet for embossing, but it is 3 cm or less.
C: There is a sheet to be embossed, and it is longer than 3 cm. D: Wrapping occurs on the embossed roll.

(3) Average single fiber diameter (μm)
Randomly collect 10 small piece samples from the spunbonded non-woven fabric, take a surface photograph of 500 to 1000 times with a microscope, measure the width of 100 fibers, 10 fibers from each sample, and measure the width of 100 fibers from the average value. The average single fiber diameter (μm) was calculated.

(4) CV value (%) of single fiber diameter
The standard deviation (μm) of the single fiber diameter was calculated from the width of a total of 100 fibers measured at the time of measuring the average single fiber diameter, and the CV value (%) of the single fiber diameter was calculated by the following formula.
-CV value (%) of single fiber diameter = standard deviation (μm) of single fiber diameter / average single fiber diameter (μm) x 100
(5) Spinning speed (m / min)
From the above average single fiber diameter and the solid density of the polyolefin resin used, the mass per 10,000 m in length was calculated as the average single fiber fineness (dtex) by rounding off to the second decimal place. Based on the average single fiber fineness and the discharge amount of resin discharged from the single hole of the spinneret (hereinafter abbreviated as single hole discharge amount) (g / min) set under each condition, the spinning speed is based on the following formula. Was calculated.
-Spinning speed (m / min) = (10000 x [single hole discharge amount (g / min)]) / [average single fiber fineness (dtex)].

(6) Metsuke of spunbonded non-woven fabric (g / m ² )
The texture of the spunbonded non-woven fabric is based on 6.2 "Mass per unit area" of JIS L1913: 2010 "General non-woven fabric test method", and 3 test pieces of 20 cm x 25 cm are collected per 1 m of sample width and standard. weigh each mass (g) in the state, representing the average value in 1 m ² per mass (g / ^{m 2).}

(7) Fluff grade A 130 mm x 200 mm test piece was collected from a spunbonded non-woven fabric, and using a Japan Society for the Promotion of Science type fastness tester, there was no load, and on the friction element side, Linley cloth-No. for heavy packaging. .. Using 314 cloth adhesive tape, it was operated 50 times, the state of fluffing was observed, and evaluation was performed according to the following fluff grade criteria. The fluff grade is preferably 3.0 grade or higher.

4.0 grade, no fluff.

3.5 grade, fluffing to the extent that small pills begin to form 3.0 grade, there are multiple small pills.

2.5 grade, large pills are clearly visible.

2.0 grade, the thinner the test piece, the more damaged it is.

1.0 grade, there was a hole in the test piece.

(8) Flexibility of spunbonded non-woven fabric (points)
The sensory evaluation of the flexibility of the spunbonded non-woven fabric was carried out, and a score was given by an absolute evaluation on a 5-point scale, with 5 points being excellent in flexibility and 1 point being inferior. This was done by 10 people and the average score was defined as flexibility (points).

(9) Average flexural rigidity B (gf · cm ² / cm) of spunbonded non-woven fabric by KES method
The average flexural rigidity B value of the spunbonded non-woven fabric was measured by a standard test by the KES method. First, three test pieces having a width of 200 mm × 200 mm were sampled in the vertical direction (longitudinal direction of the non-woven fabric) and the horizontal direction (width direction of the non-woven fabric), and 1 cm using a KES-FB2 bending characteristic tester manufactured by Kato Tech Co., Ltd. gripping the sample chuck spacing, grip the sample chuck 1cm intervals in the range of curvature -2.5 ~ + 2.5 cm ^-1, a pure bending test at a deformation rate of 0.50 cm ^-1 The measured values were averaged, and the fourth decimal place was rounded off to obtain the average flexural rigidity B value.

(10) Smooth feeling (points) of spunbonded non-woven fabric
The sensory evaluation of the tactile sensation of the spunbonded non-woven fabric was carried out, and a score was given by an absolute evaluation on a 5-point scale, with 5 points being excellent in the smoothness of the surface and 1 point being inferior. This was done by 10 people, and the average score was taken as a smooth feeling (point).

(11) Friction coefficient MIU (-) of spunbonded non-woven fabric by KES method
The coefficient of friction MIU of the spunbonded non-woven fabric was measured by a standard test by the KES method.
Three test pieces having a width of 200 mm × 200 mm are collected from the spunbonded non-woven fabric at equal intervals in the width direction of the spunbonded non-woven fabric. The test piece is set on the sample table, and the surface of the test piece is scanned with a contact friction element (material: φ0.5 mm piano wire (20 pieces in parallel), contact area: 1 cm ^{2) to which a load of 50 gf is applied, and the friction coefficient is measured.} Was measured. The above measurements were performed in the vertical direction (longitudinal direction of the non-woven fabric) and the horizontal direction (width direction of the non-woven fabric) of all the test pieces, and the average deviations of these 6 points in total were averaged and rounded to the fourth decimal place. , Friction coefficient MIU.

(Copolymer / Resin)
In each of the examples and comparative examples, the following copolymers and resins were used.

-Polyethylene polymer (A):
The α-olefin is 1-butene, and the content of α-olefin in the polymer component is 3.0 mol%. It is composed of an ethylene-1-butene copolymer with an MFR of 30 g / 10 minutes and a density of 0.950 g / cm ³ . A certain polyethylene-based polymer-Polyethylene-based polymer (B):
The α-olefin is 1-butene, and the content of α-olefin in the polymer component is 1.0 mol%. It is composed of an ethylene-1-butene copolymer having an MFR of 30 g / 10 minutes and a density of 0.955 g / cm ³ . A certain polyethylene-based polymer-Polyethylene-based polymer (C):
The α-olefin is 1-butene, and the content of α-olefin in the polymer component is 5.0 mol%. It is composed of an ethylene-1-butene copolymer having an MFR of 30 g / 10 minutes and a density of 0.945 g / cm ³ . A certain polyethylene-based polymer-Polyethylene polymer (D):
It is composed of an ethylene-1-butene copolymer in which α-olefin is 1-butene and the content of α-olefin in the polymer component is 2.0 mol%, MFR is 30 g / 10 minutes, and density is 0.953 g / cm ³ . A polyethylene-based polymer.

-Polyethylene polymer (E):
It is composed of an ethylene-1-butene copolymer in which the α-olefin is 1-butene and the content of the α-olefin in the polymer component is 0.10 mol%, the MFR is 30 g / 10 minutes, and the density is 0.960 g / cm ³ . A certain polyethylene-based polymer ・ Polyethylene polymer (F):
The α-olefin is 1-butene, and the content of α-olefin in the polymer component is 0.05 mol%. It is composed of an ethylene-1-butene copolymer with an MFR of 30 g / 10 minutes and a density of 0.962 g / cm ³ . A certain polyethylene-based polymer ・ Polyethylene-based polymer (H):
It is composed of an ethylene-1-pentene copolymer in which the α-olefin is 1-pentene and the content of the α-olefin in the polymer component is 3.0 mol%, the MFR is 30 g / 10 minutes, and the density is 0.946 g / cm ³ . A certain polyethylene-based polymer-Polyethylene-based polymer (I):
It is composed of an ethylene-1-butene copolymer in which α-olefin is 1-butene and the content of α-olefin in the polymer component is 7.0 mol%, MFR is 30 g / 10 minutes, and density is 0.930 g / cm ³ . A polyethylene-based polymer.

-Polyethylene polymer (J):
It is composed of an ethylene-1-octene copolymer in which the α-olefin is 1-octene and the content of the α-olefin in the polymer component is 3.0 mol%, the MFR is 30 g / 10 minutes, and the density is 0.935 g / cm ³ . A certain polyethylene-based polymer ・ Polyethylene-based polymer (K):
It is composed of an ethylene-1-octene copolymer in which the α-olefin is 1-octene and the content of the α-olefin in the polymer component is 7.0 mol%, the MFR is 30 g / 10 minutes, and the density is 0.928 g / cm ³ . A certain polyethylene-based polymer-polyolefin-based resin (L):
A polypropylene resin composed of a homopolymer having a melting point of 163 ° C. and an MFR of 30 g / 10 minutes.

(Example 1)
The polyethylene-based polymer (A) was melted by an extruder, and the yarn spun at a spinning temperature of 240 ° C., a pore diameter of 0.40 mm, and a single-hole discharge rate of 0.55 g / min was cooled and solidified. After that, a non-woven fiber web made of polyethylene-based polymer filaments was obtained by pulling and stretching the ejector with compressed air having a pressure of 0.40 MPa with a rectangular ejector and collecting the mixture on a moving net. Regarding spinnability, the number of yarn breaks was as good as 0 times / ton.

Subsequently, the obtained non-woven fiber web was embossed with a metal flat roll on the lower roll with a crimping ratio of 16% and a metal polka dot pattern engraved on the upper roll. Using a roll, the thermal bonding temperature of the spunbonded non-woven fabric ^{having a grain size of 30 g / m 2} was examined under the condition of a linear pressure of 30 N / cm. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 138 ° C., no sheet was taken off from the embossed roll, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 2)
Using the polyethylene-based polymer (A) as the sheath component and the polyolefin-based resin (L) as the core component, they are melted by separate extruders, and the mass of the sheath component and the core component is increased by a concentric core sheath cap. A spunbonded non-woven fabric made of polyethylene-based polymer long fibers was obtained by the same method as in Example 1 except that the mixture was weighed and spun so that the ratio was 50:50. Regarding spinnability, the number of yarn breaks was as good as 0 times / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 138 ° C., no sheet was taken off from the embossed roll, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 3)
Regarding the spinnability of the spunbonded non-woven fabric made of polyethylene-based polymer long fibers by the same method as in Example 1 except that the polyethylene-based polymer was the polyethylene-based polymer (B), the number of yarn breaks was 0. It was good at / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 140 ° C., no sheet was taken off from the embossed roll, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 4)
A spunbonded nonwoven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that the polyethylene-based polymer was the polyethylene-based polymer (C). Regarding spinnability, the number of yarn breaks was as good as 1.5 times / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 134 ° C., the sheet was taken to the embossed roll to 3 cm or less, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 5)
A spunbonded nonwoven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that the polyethylene-based polymer was the polyethylene-based polymer (H). Regarding spinnability, the number of yarn breaks was as good as 1.5 times / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 134 ° C., the sheet was taken to the embossed roll to 3 cm or less, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 6)
The obtained non-woven fiber web is used as an embossed roll with a crimping ratio of 11%, which is made of metal and has a polka dot pattern engraved on the upper roll, and a pair of upper and lower thermal embossed rolls composed of a metal flat roll is used on the lower roll. A spunbonded non-woven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that it was heat-bonded using. Regarding spinnability, the number of yarn breaks was as good as 0 times / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 138 ° C., no sheet was taken off from the embossed roll, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 7)
A spunbonded nonwoven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that the polyethylene-based polymer was the polyethylene-based polymer (D). Regarding spinnability, the number of yarn breaks was as good as 0 times / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 138 ° C., no sheet was taken off from the embossed roll, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 8)
The obtained non-woven fiber web is used as an embossed roll with a crimping ratio of 11%, which is made of metal and has a polka dot pattern engraved on the upper roll, and a pair of upper and lower thermal embossed rolls composed of a metal flat roll is used on the lower roll. A spunbonded non-woven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 7 except that it was heat-bonded using. Regarding spinnability, the number of yarn breaks was as good as 0 times / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 138 ° C., no sheet was taken off from the embossed roll, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 9)
The obtained non-woven fiber web is used as an embossed roll with a crimping ratio of 14%, which is made of metal and has a polka dot pattern engraved on the upper roll, and a pair of upper and lower thermal embossed rolls composed of a metal flat roll is used on the lower roll. A spunbonded non-woven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that it was heat-bonded using. Regarding spinnability, the number of yarn breaks was as good as 0 times / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 138 ° C., no sheet was taken off from the embossed roll, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 10)
The obtained non-woven fiber web is embossed with a metal polka dot pattern engraved on the upper roll with a pressure bonding ratio of 8%, and a pair of upper and lower thermal embossed rolls composed of metal flat rolls are used on the lower roll. A spunbonded non-woven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that it was heat-bonded using. Regarding spinnability, the number of yarn breaks was as good as 0 times / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 140 ° C., the sheet was taken to the embossed roll to 3 cm or less, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Example 11)
A spunbonded nonwoven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that the polyethylene-based polymer was the polyethylene-based polymer (E). Regarding spinnability, the number of yarn breaks was as good as 2.0 times / ton. At the time of heat-bonding the embossed roll, there was no fluffing under the condition that the heat-bonding temperature was 142 ° C., the sheet was taken to the embossed roll to 3 cm or less, and the heat-bonding property was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 1.

(Comparative Example 1)
A spunbonded nonwoven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that the polyethylene-based polymer was the polyethylene-based polymer (I). Regarding spinnability, yarn breakage occurred more than 5.0 times / ton, and spinnability was poor. When the embossed roll was adhered, fluffing of the sheet was observed, and when the temperature condition of the embossed roll was raised to 130 ° C., wrapping around the roll occurred frequently and the sheet could not be collected.

(Comparative Example 2)
A spunbonded nonwoven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 2 except that the polyethylene-based polymer was the polyethylene-based polymer (I). Regarding spinnability, the number of yarn breaks was 2.5 times / ton, which was poor. During heat bonding of the embossed roll, fluffing of the sheet was observed, and when the temperature condition of the embossed roll was raised to 130 ° C., wrapping around the roll occurred frequently and it was difficult to collect the sheet.

(Comparative Example 3)
A spunbonded nonwoven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that the polyethylene-based polymer was the polyethylene-based polymer (J). Regarding spinnability, the number of yarn breaks was 4.2 times / ton, which was poor. At the time of heat bonding of the embossed roll, fluffing was observed under the condition that the heat bonding temperature was 130 ° C. , The heat adhesion was poor. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 2.

(Comparative Example 4)
A spunbonded nonwoven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that the polyethylene-based polymer was the polyethylene-based polymer (K). Regarding spinnability, yarn breakage occurred more than 5.0 times / ton, and spinnability was poor. During heat bonding of the embossed roll, fluffing of the sheet was observed, and when the embossed roll temperature was raised to 128 ° C., wrapping around the roll occurred frequently, making it difficult to collect the sheet.

(Comparative Example 5)
The obtained non-woven fiber web is embossed with a metal polka dot pattern engraved on the upper roll with a crimping ratio of 7%, and a pair of upper and lower thermal embossed rolls composed of metal flat rolls are used on the lower roll. A spunbonded non-woven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that it was heat-bonded using. Regarding spinnability, the number of yarn breaks was as good as 0 times / ton. At the time of heat bonding of the embossed roll, fluffing was observed under the condition that the heat bonding temperature was 142 ° C. , The heat adhesion was poor. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 2.

(Comparative Example 6)
The obtained non-woven fiber web is embossed with a metal polka dot pattern engraved on the upper roll with a pressure bonding ratio of 20%, and a pair of upper and lower thermal embossed rolls composed of metal flat rolls are used on the lower roll. A spunbonded non-woven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that it was heat-bonded using. Regarding spinnability, the number of yarn breaks was as good as 0 times / ton. At the time of heat-bonding the embossed roll, although there was no fluffing under the condition that the heat-bonding temperature was 138 ° C., the sheet was taken off to the embossed roll by 5 cm or more, which was inferior in heat-bonding property. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 2.

(Comparative Example 7)
A spunbonded nonwoven fabric made of polyethylene-based polymer filaments was obtained by the same method as in Example 1 except that the polyethylene-based polymer was the polyethylene-based polymer (F). Regarding spinnability, the number of yarn breaks was 2.9 times / ton, which was poor. At the time of heat bonding of the embossed roll, there is no fluffing under the condition that the heat bonding temperature is 142 ° C. , The heat adhesion was poor. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 2.

(Comparative Example 8)
A spunbonded nonwoven fabric made of polyolefin long fibers was obtained by the same method as in Example 1 except that the polyolefin resin (L) was used instead of the polyethylene polymer. Regarding spinnability, the number of yarn breaks is as good as 0 times / ton, and when the embossed roll is heat-bonded, no fluffing is observed under the condition that the heat-bonding temperature is 138 ° C. It was not taken off, and the heat adhesion was good. For the obtained spunbonded non-woven fabric, the average single fiber diameter, the CV value of the single fiber diameter, the spinning speed, the fluff grade, the texture (flexibility), the average bending rigidity B by the KES method, the texture (smooth feeling), and the friction by the KES method. The coefficient MIU was measured and evaluated. The results are shown in Table 2.

The polyethylene-based polymers of Examples 1 to 11 are copolymers of ethylene and α-olefins having 3 to 5 carbon atoms, and the content of α-olefins is 0.10 to 5 in the polymerized components of the polyethylene-based polymers. The non-woven fabric having a pressure ratio of 0.0 mol% and an embossing roll of 8 to 19% had good spinnability / thermal adhesion, and had high flexibility / smoothness on the surface. In addition, the fluff resistance was also good. In particular, the spunbonded non-woven fabrics of Examples 6 and 8 were excellent in all of spinnability / heat adhesion / fluff resistance / flexibility / surface smoothness, and were particularly suitable as sanitary materials.

On the other hand, the α-olefins shown in Comparative Examples 1 to 8 have 6 or more carbon atoms, the content of the α-olefin in the polymerization component is less than 0.10 mol%, or the polyethylene-based polymer exceeds 5 mol%, and the pressure-bonding ratio is 7%. The spunbonded non-woven fabric having the following or 20% or more is not only inferior in at least one of spinnability / thermal adhesiveness and low production stability as compared with the non-woven fabric of the present invention, but also has flexibility / surface smoothness. It was low. Further, the spunbonded nonwoven fabric made of a polyolefin-based polymer other than the polyethylene-based polymer is superior in spinnability / thermal adhesiveness as compared with the nonwoven fabric of the present invention, but has further lower flexibility / smoothness on the surface. there were.

Claims

It is composed of fibers containing a polyethylene-based polymer, and the polyethylene-based polymer is a copolymer of ethylene and α-olefin having 3 to 5 carbon atoms, and the content of α-olefin in the polymerization component of the polyethylene-based polymer is high. A spunbonded non-woven fabric having a pressure-bonding ratio of 0.10 to 5.0 mol% and a non-woven fabric having a pressure-bonding ratio of 8 to 19%.
The spunbonded nonwoven fabric according to claim 1, wherein the α-olefin is 1-butene.
The spunbonded nonwoven fabric according to claim 1 or 2, wherein the α-olefin content is 0.10 to 3.0 mol%.
The spunbonded non-woven fabric according to any one of claims 1 to 3, wherein the crimping ratio of the non-woven fabric is 8 to 14%.