JP7048150B2 - Non-woven fabric - Google Patents

Description

The present invention relates to a non-woven fabric.

Nonwoven fabrics using propylene-based polymers (polypropylene nonwoven fabrics) are widely used in various applications because they are excellent in breathability, flexibility, and lightness. Therefore, the non-woven fabric is required to have various characteristics according to its use, and is also required to improve the characteristics.
On the other hand, since polypropylene non-woven fabric is hydrophobic in nature, it is essential to treat it with hydrophilicity in order to use it for top sheets of sanitary materials such as disposable diapers and sanitary napkins, wipers and the like.

Fibers obtained by adding and mixing, for example, a specific propylene / α-olefin random copolymer and a specific nonionic surfactant as a nonwoven fabric that develops hydrophilicity in a short time after the manufacture of the nonwoven fabric. A non-woven fabric comprising the above is disclosed (see, for example, Patent Documents 1 and 2).

International Publication No. 2010/024147 Japanese Unexamined Patent Publication No. 2010-150674

However, in the non-woven fabric obtained by the conventional method of treating the surface of the polypropylene non-woven fabric with a surfactant, further improvement in hydrophilicity may be required. However, there is a limit to the improvement of hydrophilicity by simply increasing the amount of the hydrophilic agent added, and there is a case where yarn breakage is likely to occur during spinning.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a nonwoven fabric which is less likely to cause yarn breakage during spinning and has excellent hydrophilicity.
As a result of the examination by the inventors, it was found that the non-woven fabric containing the fiber containing a specific propylene / ethylene random copolymer, a specific ethylene-based polymer, and a specific surfactant has excellent hydrophilicity. ..

Means for solving the above problems include the following embodiments.
<1> 100 parts by mass of a propylene / α-olefin random copolymer having a melting point (Tm) in the range of 125 ° C to 155 ° C.
1 part by mass to 10 parts by mass of an ethylene polymer having a crystallinity of 45% to 85%,
Containing 0.5 parts by mass to 5 parts by mass of a surfactant,
The surfactant is a non-woven fabric containing fibers, which contains a polyoxyalkylene alkyl ether.
<2> The nonwoven fabric according to <1>, wherein the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the ethylene polymer is 4.0 or more.
<3> The nonwoven fabric according to <1> or <2>, further comprising an ethylene-based polymer wax having a weight average molecular weight (Mw) of 400 to 15,000.
<4> The melt flow rate (MFR) of the ethylene polymer is 2 g / 10 minutes to 25.
The nonwoven fabric according to any one of <1> to <3>, which is g / 10 minutes.
<5> The nonwoven fabric according to any one of <1> to <4>, wherein the surfactant further contains a polyoxyalkylene alkylamide and a glycerin monofatty acid ester.
<6> The polyoxyalkylene alkyl ether is 30% by mass to 60% by mass, the polyoxyalkylene alkylamide is 20% by mass to 50% by mass, and the glycerin monofatty acid ester is added to the total mass of the surfactant. The non-woven fabric according to <5>, which contains 20% by mass to 50% by mass.
<7> The nonwoven fabric according to any one of <1> to <6>, which is a spunbonded nonwoven fabric.

According to the present invention, it is possible to provide a non-woven fabric which is less likely to cause yarn breakage during spinning and has excellent hydrophilicity.

In the present specification, the numerical range indicated by using "-" indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively. In the numerical range described in the present specification stepwise, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in another stepwise description. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.
In the present specification, the amount of each component in the composition is the total amount of the plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition. Means.
In the present specification, the propylene-based copolymer means a copolymer in which the content of propylene with respect to all the constituent units of the copolymer is 50% by mass or more.
In the present specification, the ethylene-based polymer means a polymer in which the content of ethylene with respect to all the constituent units of the polymer is 50% by mass or more.

《Non-woven fabric》
The non-woven fabric according to the present disclosure has 100 parts by mass of a propylene / α-olefin random copolymer having a melting point (Tm) in the range of 125 ° C. to 155 ° C. and an ethylene polymer having a crystallinity of 45% to 85%. It contains 1 part by mass to 10 parts by mass and 0.5 part by mass to 5 parts by mass of a surfactant, and the surfactant contains a fiber containing a polyoxyalkylene alkyl ether.
Since the fibers constituting the nonwoven fabric of the present disclosure contain a specific amount of a specific propylene / α-olefin random copolymer, a specific ethylene-based polymer, and a surfactant containing a polyoxyalkylene alkyl ether, each of them contains a specific amount. It is less likely to break during spinning and has excellent hydrophilicity. The reason for this is not clear, but it can be inferred as follows.

It is considered that when the surfactant is unevenly distributed on the surface of the non-woven fabric, it has excellent hydrophilicity. In the nonwoven fabric according to the present disclosure, by combining the polypropylene-based copolymer and the ethylene-based polymer having a specific crystallinity, the polyoxyalkylene alkyl ether passes through the non-crystalline portion of the polypropylene-based copolymer. It is presumed that the non-woven fabric tends to be unevenly distributed on the surface of the fiber, and as a result, the non-woven fabric is superior in hydrophilicity.
Further, since the nonwoven fabric according to the present disclosure contains fibers containing an ethylene polymer having a crystallinity within a specific range and a specific amount of a surfactant, it is presumed that yarn breakage is unlikely to occur during spinning. Will be done.
Hereinafter, each component of the fiber constituting the nonwoven fabric according to the present disclosure will be described.

(Propene / α-olefin random copolymer)
The fibers constituting the nonwoven fabric according to the present disclosure include a propylene / α-olefin random copolymer having a melting point (Tm) in the range of 125 ° C. to 155 ° C.
The fibers constituting the nonwoven fabric according to the present disclosure are excellent in hydrophilicity by containing a propylene / α-olefin random copolymer.

The α-olefin to be copolymerized with propylene is preferably an α-olefin having 2 or more carbon atoms excluding propylene, and has 2 or 4 to 8 carbon atoms, from the viewpoint of obtaining a non-woven fabric having excellent initial hydrophilicity. The α-olefin of the above is more preferable, and the α-olefin having 2 carbon atoms, that is, ethylene is further preferable.
Specific examples of such α-olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene and the like.
The α-olefin may be used alone or in combination of two or more.

The melting point (Tm) of the propylene / α-olefin random copolymer is in the range of 125 ° C to 155 ° C.
When the melting point (Tm) of the propylene / α-olefin random copolymer is 125 ° C. or higher, yarn breakage is small and stable spinning can be performed. Further, when the melting point (Tm) of the propylene / α-olefin random copolymer is 155 ° C. or lower, the hydrophilicity is excellent.
From the above viewpoint, the melting point (Tm) of the propylene / α-olefin random copolymer is preferably in the range of 125 ° C to 150 ° C, more preferably in the range of 130 ° C to 147 ° C.

The melt flow rate (MFR) (ASTM D-1238, 230 ° C., load 2160 g) of the propylene / α-olefin random copolymer is not particularly limited as long as the propylene / α-olefin random copolymer can be melt-spun. However, it is preferably in the range of 1 g / 10 minutes to 500 g / 10 minutes, more preferably 5 g / 10 minutes to 200 g / 10 minutes, and further preferably 10 g / 10 minutes to 100 g / 10 minutes.

The melting point (Tm) of the propylene / α-olefin random copolymer can be measured using a differential scanning calorimeter (DSC).
With a differential scanning calorimeter (DSC), the temperature was raised to a temperature about 50 ° C. higher than the temperature giving the extreme value of the melting heat absorption curve when the temperature was raised at a heating rate of 10 ° C./min, and the temperature was maintained at this temperature for 10 minutes. After that, the temperature was cooled to 30 ° C. at a temperature lowering rate of 10 ° C./min, and the melting curve when the temperature was raised to a predetermined temperature at a temperature rising rate of 10 ° C./min was measured again. Following this, the temperature (Tp) that gives the extreme value of the melting heat absorption curve can be obtained, and the heat absorption peak at such a peak temperature can be obtained as the melting point (Tm).

The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the propylene / α-olefin random copolymer is preferably 1.5 to 5.0. Mw / Mn is more preferably in the range of 1.5 to 4.5 in that fibers having good spinnability and particularly excellent fiber strength can be obtained.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the propylene / α-olefin random copolymer are determined by GPC (gel permeation chromatography) by the weight average molecular weight (Mw) and the number of the ethylene-based polymer described later. It can be obtained in the same manner as the method for measuring the average molecular weight (Mn).

The density of the propylene / α-olefin random copolymer is preferably in the range of 0.895 g / cm ³ to 0.915 g / cm ³ , more preferably 0.900 g / cm ³ to 0.915 g / cm ³ , and 0. 905 g / cm ³ to 0.910 g / cm ³ is more preferable.
In the present disclosure, the density is a value obtained by measuring according to the density gradient method of JIS K7112 (1999).

The content of α-olefin in the propylene / α-olefin random copolymer is not particularly limited as long as the melting point (Tm) of the propylene / ethylene random copolymer is within the above range, and is 0.5 mol% to 10%. It is preferably mol%, more preferably 3 mol% to 8 mol%, still more preferably 4 mol% to 7 mol%.

The content of the propylene / α-olefin random copolymer is preferably 85% by mass or more, preferably 90% by mass or more, based on the total mass of the resin composition from the viewpoint of further improving the spinnability. Is more preferable, and 90% by mass to 99% by mass is further preferable.

(Ethylene polymer)
The fibers constituting the nonwoven fabric according to the present disclosure contain an ethylene polymer having a crystallinity of 45% to 85%. The ethylene-based polymer is a homopolymer of ethylene or a copolymer of ethylene and another α-olefin, and the content of ethylene is 50% by mass or more of all the constituent units.

Other α-olefins copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-. Examples thereof include α-olefins having 3 to 20 carbon atoms such as tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosen. These ethylene-based polymers may be one kind alone or a mixture of two or more kinds.

The crystallinity of the ethylene-based polymer contained in the fibers constituting the nonwoven fabric according to the present disclosure is 45% to 85%. When the crystallinity of the ethylene-based polymer is 45% to 85%, the polyoxyalkylene alkyl ether contained in the surfactant tends to be unevenly distributed on the fiber surface, and it is presumed that the hydrophilicity is excellent.
The crystallinity of the ethylene-based polymer can be adjusted to a desired crystallinity by changing the type of catalyst, pressure, and the like in the polymerization reaction.
From the viewpoint of obtaining a nonwoven fabric having better hydrophilicity, the crystallinity of the ethylene polymer is preferably 60% to 85%, more preferably 65% to 85%. It is presumed that the crystallinity of the ethylene-based polymer is 60% or more, preferably 65% or more, so that the uneven distribution of the polyoxyalkylene alkyl ether on the fiber surface is further promoted.
The crystallinity of the ethylene-based polymer can be determined by X-ray diffraction, and can be determined by dividing the peak area of the obtained crystalline material by the total peak area of the ethylene-based polymer.

The melt flow rate (MFR) (ASTM D 1238, 190 ° C., load 2160 g) of the ethylene polymer is particularly high as long as the ethylene polymer can be melt-spun by mixing with the propylene / α-olefin random copolymer. There is no limitation. The MFR of the ethylene polymer is preferably in the range of 1 g / 10 min to 50 g / 10 min, and in the range of 2 g / 10 min to 25 g / 10 min, from the viewpoint of fiber spinnability, fiber diameter and strength. It is more preferable that the amount is in the range of 2 g / 10 minutes to 10 g / 10 minutes.
When the melt flow rate (MFR) of the ethylene-based polymer is in the above range, the spinnability of the resin composition is good, and the obtained nonwoven fabric is further excellent in strength.

The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the ethylene polymer is preferably 4 or more, preferably 5 to 15, from the viewpoint of further improving the hydrophilicity. It is more preferable, and it is further preferable that it is 6 to 13.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the ethylene polymer are values obtained from the gel permeation chromatography (GPC) method and are measured under the following conditions.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) are obtained by preparing a calibration curve using commercially available monodisperse standard polystyrene and using the following conversion method.

Equipment: HLC8321 GPC / HT (manufactured by Tosoh Corporation)
Solvent: O-dichlorobenzene Column: 2 TSKgel GMH6-HT, 2 TSKgel GMH6-HTL columns (manufactured by Tosoh Corporation)
Flow rate: 1.0 ml / min Sample: O-dichlorobenzene solution 0.10 mg / mL
Temperature: 140 ° C
Molecular weight conversion: Polypropylene (PP) conversion / general-purpose calibration method

In addition, the coefficient of the Mark-Houwink viscosity formula shown below was used for the calculation of the general-purpose calibration.
Polystyrene (PS) coefficient: KPS = 1.38 × 10 ^-4 , aPS = 0.70
Coefficient of polypropylene (PP): KPP = 2.42 × 10 ^-4 , aPP = 0.707

The content of the ethylene-based polymer is preferably 1 part by mass to 10 parts by mass with respect to 100 parts by mass of the propylene / α-olefin random copolymer from the viewpoint of obtaining a non-woven fabric having better hydrophilicity. It is more preferably 2 parts by mass to 8 parts by mass, further preferably 2 parts by mass to 6 parts by mass, and particularly preferably 2.5 parts by mass to 5 parts by mass.

As the ethylene-based polymer, a polymer obtained by various known production methods, for example, a medium-low pressure method obtained by using a high-pressure method, a Ziegler catalyst, or a metallocene catalyst may be used.
Among these, when an ethylene-based polymer obtained by polymerization with a metallocene-based catalyst is used, it is preferable in that the spinnability of the resin composition becomes better and the strength of the nonwoven fabric becomes better.

<Surfactant>
The fibers constituting the nonwoven fabric according to the present disclosure contain a surfactant, and the surfactant contains a polyoxyalkylene alkyl ether.
The polyoxyalkylene portion of the polyoxyalkylene alkyl ether is preferably oxyethylene from the viewpoint of obtaining a nonwoven fabric having better hydrophilicity.
From the same viewpoint, the polyoxyalkylene alkyl ether is preferably an ethylene oxide adduct of an aliphatic alcohol, and more preferably a compound represented by the following formula (1).

In the formula, R represents a hydrocarbon group having 12 to 30 carbon atoms, x represents the average number of added moles, and represents an integer of 1 to 20. )

The hydrocarbon group having 12 to 30 carbon atoms may be a straight chain, a branched chain, or a saturated or unsaturated hydrocarbon group.
Among these, a linear hydrocarbon group is preferable, a linear saturated hydrocarbon group is more preferable, and a straight chain having 14 to 20 carbon atoms is preferable, from the viewpoint of obtaining a non-woven fabric having more excellent hydrophilicity. It is more preferably a saturated hydrocarbon group.

The content of the polyoxyalkylene alkyl ether is preferably 30% by mass to 60% by mass, preferably 40% by mass to 55% by mass, based on the total mass of the surfactant contained in the fibers constituting the nonwoven fabric according to the present disclosure. More preferably, it is by mass.

The surfactant preferably further contains at least one of polyoxyalkylene alkylamide and glycerin monofatty acid ester, and may contain polyoxyalkylene alkylamide and glycerin monofatty acid ester, from the viewpoint of obtaining a non-woven fabric having better hydrophilicity. More preferred.

The polyoxyethylene alkyl amide is preferably a compound represented by the following formula (2) from the viewpoint of obtaining a non-woven fabric having better hydrophilicity.

In the formula, R ¹ represents a hydrocarbon group having 16 to 18 carbon atoms, y and z independently represent an integer of 1 or more, and y + z represents an integer of 5 or more and 10 or less.

The hydrocarbon group having 16 to 18 carbon atoms may be a straight chain, a branched chain, or a saturated or unsaturated hydrocarbon group.
The hydrocarbon group having 16 to 18 carbon atoms is preferably a straight-chain hydrocarbon group, and more preferably a straight-chain saturated hydrocarbon group, from the viewpoint of obtaining a nonwoven fabric having better hydrophilicity.

The content of the polyoxyalkylene alkylamide is preferably 20% by mass to 50% by mass, more preferably 20% by mass to 40% by mass, based on the total mass of the surfactant contained in the fiber. preferable.

The glycerin monofatty acid ester may be a glycerin monofatty acid ester of a linear or branched fatty acid, or a glycerin monofatty acid ester of a saturated or unsaturated fatty acid.
From the viewpoint of obtaining a non-woven fabric having better hydrophilicity, the glycerin monofatty acid ester is preferably a glycerin monofatty acid ester of a linear saturated fatty acid, and is a glycerin monofatty acid ester having 16 to 18 carbon atoms of the linear saturated fatty acid. It is more preferable to have.

From the viewpoint of obtaining a non-woven fabric having more excellent hydrophilicity, the content of the glycerin monofatty acid ester is preferably 20% by mass to 50% by mass, preferably 20% by mass, based on the total mass of the surfactant contained in the fiber. More preferably, it is% to 40% by mass.

The content of the surfactant is 0.5 parts by mass to 5 parts by mass with respect to 100 parts by mass of the propylene / α-olefin random copolymer.
When the content of the surfactant is 0.5 parts by mass or more with respect to 100 parts by mass of the propylene / α-olefin random copolymer, a nonwoven fabric having better hydrophilicity can be obtained. Further, when the content of the surfactant is 5 parts by mass or less with respect to 100 parts by mass of the propylene / α-olefin random copolymer, yarn breakage during spinning is unlikely to occur.
From the above viewpoint, the content of the surfactant is preferably 1 part by mass to 4 parts by mass, and more preferably 1 part by mass to 3 parts by mass.

From the viewpoint of obtaining a non-woven fabric having more excellent hydrophilicity, the fibers constituting the non-woven fabric according to the present disclosure contain 30% by mass to 60% by mass of polyoxyalkylene alkyl ether and polyoxyalkylene with respect to the total mass of the surfactant. It is preferable to contain 20% by mass to 50% by mass of alkylamide and 20% by mass to 50% by mass of glycerin monofatty acid ester.

The surfactant may be incorporated inside the fiber or may be attached to the surface of the fiber. From the viewpoint of maintaining hydrophilicity even after repeated use, it is preferable that the surfactant is incorporated into the fiber and the hydrophilic portion is unevenly distributed on the surface of the fiber.
As a method for incorporating the surfactant into the fiber, for example, the surfactant is added to a resin composition containing the above-mentioned propylene / α-olefin random copolymer and the above-mentioned ethylene-based polymer. , Melting and spinning to form fibers.
Further, as a method of adhering the interface active agent to the surface of the fiber, for example, a resin composition containing the above-mentioned propylene / α-olefin random copolymer and the above-mentioned ethylene-based polymer is melted and spun. After forming the fiber, a method of applying a surfactant to the surface of the fiber to form the fiber to which the surfactant adheres to the surface can be mentioned.
The method of applying the surfactant to the surface of the fiber is not particularly limited, and is a publicly known public method such as a method of immersing the fiber in a solution containing a surfactant and a method of applying a solution containing a surfactant to the fiber. Can be attached to the surface of the fiber.

(Ethylene polymer wax)
As another embodiment, the fibers constituting the nonwoven fabric according to the present disclosure may contain an ethylene-based polymer wax, if necessary.
From the viewpoint that the effect of improving the dispersibility between the propylene / α-olefin random copolymer and the ethylene-based polymer can be obtained and the spinnability can be further improved, the fiber constituting the non-woven fabric according to the present disclosure is ethylene. It is preferable to further contain the polymer wax.
In the present specification, the ethylene-based polymer wax refers to a wax-like polymer having a lower molecular weight than the above-mentioned ethylene-based polymer.

The ethylene-based polymer wax may be either a homopolymer of ethylene or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms.
When a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms is used as the ethylene-based polymer wax, the carbon number of the α-olefin to be copolymerized with ethylene is more preferably 3 to 8, and the number of carbon atoms is more preferable. 3 or 4 is more preferable, and carbon number 3 is further preferable.
When the number of carbon atoms of the α-olefin to be copolymerized with ethylene is in the above range, the spinnability is improved and the properties such as the strength of the nonwoven fabric can be enhanced.
When an ethylene homopolymer is used as the ethylene-based polymer wax, it has excellent kneadability with the ethylene-based polymer and excellent spinnability.
Further, the ethylene-based polymer wax may be used alone or as a mixture of two or more kinds thereof.

The weight average molecular weight (Mw) of the ethylene polymer wax is preferably in the range of 15,000 or less. It is preferably in the range of less than 15,000, more preferably in the range of 9000 or less, further preferably in the range of 6000 or less, particularly preferably in the range of less than 6000, and most preferably in the range of 5000 or less. preferable.
The lower limit is preferably 400 or more, and more preferably 1000 or more.
When the weight average molecular weight (Mw) of the ethylene-based polymer wax is within the above range, the spinnability of the resin composition is likely to be improved, the fiber diameter is likely to be reduced, and stability over time is obtained. It will be easier.
Further, when the nonwoven fabric according to the present disclosure is laminated with, for example, a melt blown nonwoven fabric formed from an ethylene-based polymer or the like to form a nonwoven fabric laminate, it is preferable in that the adhesiveness between the layers tends to be excellent.

The weight average molecular weight (Mw) of the ethylene-based polymer wax is a value obtained from a gel permeation chromatography (GPC) method, and is a value measured under the following conditions.
The weight average molecular weight is obtained by preparing a calibration curve using commercially available monodisperse standard polystyrene and using the following conversion method.

Equipment: Gel permeation chromatograph Alliance GPC2000 type (manufactured by Waters)
Solvent: o-dichlorobenzene Column: TSKgel column (manufactured by Toso Co., Ltd.) x 4
Flow rate: 1.0 ml / min Sample: 0.15 mg / mLo-dichlorobenzene solution Temperature: 140 ° C
Molecular weight conversion: PE conversion / general-purpose calibration method The coefficients of the Mark-Houwink viscosity formula shown below were used for the calculation of general-purpose calibration.
Polystyrene (PS) coefficient: KPS = 1.38 × ^10-4 , aPS = 0.70
Coefficient of polyethylene (PE): KPE = 5.06 × ^10-4 , aPE = 0.70

The ethylene-based polymer wax preferably has a softening point in the range of 90 ° C. to 145 ° C., more preferably 90 ° C. to 130 ° C., as measured according to JIS K2207 (2006).

From the viewpoint of making the fiber finer and improving the strength of the fiber, the content of the ethylene-based polymer wax is 0.1 part by mass or more with respect to 100 parts by mass of the propylene / α-olefin random copolymer. It is preferably 10 parts by mass, more preferably 0.5 parts by mass to 5 parts by mass.

The method for producing the ethylene-based polymer wax is not particularly limited, and either a method for producing a low molecular weight polymer that is usually used, or a method for reducing the molecular weight of a high-molecular-weight ethylene-based polymer by heating and reducing the molecular weight. It may be the manufacturing method of.

Further, the ethylene-based polymer wax may be purified by a method such as solvent separation in which the wax is separated by the difference in solubility in a solvent, or distillation.
When the ethylene-based polymer wax is obtained by a commonly used method for producing a low molecular weight polymer by polymerization, various known production methods such as Ziegler / Natta catalyst and JP-A-08-239414, International Publication No. It can be produced by the production method described in 2007/114102 or the like, which polymerizes with a metallocene-based catalyst or the like.

The density of the ethylene-based polymer wax is not particularly limited, and is preferably 0.890 g / cm ³ to 0.980 g / cm ³ , more preferably 0.910 g / cm ³ or more, and 0.920 g. It is more preferably / cm ³ or more.
The density of the ethylene polymer wax is preferably 0.960 g / cm ³ or less, and more preferably 0.950 g / cm ³ or less.
When an ethylene-based polymer wax having a density within the above range is used, the spinnability of the resin composition tends to be excellent. Further, when the nonwoven fabric according to the present disclosure is laminated with, for example, a meltblown nonwoven fabric made of an ethylene polymer or the like to form a nonwoven fabric laminate, it is also preferable that the nonwoven fabric tends to have excellent adhesiveness between layers.

The difference between the density of the propylene / α-olefin copolymer and the density of the ethylene-based polymer wax is not particularly limited, and is preferably smaller than 0.35 g / cm ³ and 0.20 g / cm ³ . It is more preferably smaller, and even more preferably less than 0.15 g / cm ³ .
When the density difference is within the above range, the spinnability is improved and the strength and other characteristics of the nonwoven fabric can be enhanced.

For the production of the propylene-based copolymer composition used for the fiber constituting the nonwoven fabric according to the present disclosure, conventionally known catalysts, for example, JP-A-57-63310, JP-A-58-83006, JP-A-P. Magnesium-supported titanium catalysts described in Japanese Patent Laid-Open No. 3-706, Japanese Patent No. 3476793, Japanese Patent Laid-Open No. 4-218508, Japanese Patent Laid-Open No. 2003-105022, etc., International Publication No. 2001/53369, International Publication No. 2001 The metallocene catalyst described in / 27124, JP-A-3-193996, or JP-A-02-41303 can be preferably used.

The fibers constituting the non-woven fabric according to the present disclosure, in addition to the propylene / α-olefin random copolymer, the ethylene-based polymer, the above-mentioned surfactant, and the ethylene-based polymer wax, further impair the object of the present invention. To the extent that it does not, it can contain any other component that can be used as needed. Each of these components can be mixed using various known methods.

Any other components that can be used as needed include other polymers, colorants, antioxidants such as phosphorus and phenols, weather stabilizers such as benzotriazoles, and lightfast stables such as hindered amines. Agents, blocking inhibitors, dispersants such as calcium stearate, lubricants, nucleating agents, pigments, softeners, hydrophilic agents other than the above surfactants, water repellents, auxiliaries, water repellents, fillers, antibacterial agents, pesticides , Various known additives such as insect repellents, chemicals, natural oils, synthetic oils and the like.

The non-woven fabric according to the present disclosure is not particularly limited. , Needle punched nonwoven fabrics and the like, and various known short-fiber nonwoven fabrics and long-fiber nonwoven fabrics (for example, long-fiber cellulose nonwoven fabrics) can be mentioned.
Among these, from the viewpoint of the strength of the non-woven fabric, the non-woven fabric is preferably a spunbonded non-woven fabric.
Further, the nonwoven fabric may have a single-layer structure or a laminated structure of two or more layers.

Further, the fiber constituting the nonwoven fabric according to the present disclosure is a single fiber containing the above-mentioned propylene / α-olefin random copolymer, the ethylene-based polymer, and the resin composition containing at least the above-mentioned specific surfactant. Also, a composite fiber having a side-by-side, core-sheath structure containing the above resin composition may be used as long as the object of the present invention is not impaired.

The cross-sectional shape of the fibers constituting the nonwoven fabric according to the present disclosure may be a round shape, a star shape, a polygonal shape such as a triangular shape, a square shape, a pentagonal shape, an elliptical shape, or a hollow shape.

The non-woven fabric according to the present disclosure includes other fibers in addition to the above-mentioned propylene / α-olefin random copolymer, the ethylene-based polymer, and the above-mentioned fiber containing at least the specific surfactant, as long as the object of the present invention is not impaired. For example, it may be a non-woven fabric containing mixed fibers obtained by mixing fibers obtained from other olefin-based polymers having different resin compositions, polyester, thermoplastic elastomer, and the like.

<Physical characteristics of non-woven fabric>
The non-woven fabric according to the present disclosure preferably has an air permeability of 500 cm ³ / cm ² / s or less measured under the condition of a flow rate with a pressure difference of 125 Pa by a Frazier air permeability measuring machine according to JIS L 1096 (2010). 450 cm ³ / cm ² / s or less is more preferable, and 400 cm ³ / cm ² / s or less is further preferable. The lower limit of the air permeability is not particularly limited, but may be 50 cm ³ / cm ² / s or more. The air permeability is preferably 100 cm ³ / cm ² / s or more, and more preferably 200 cm ³ / cm ² / s or more.
When the air permeability of the non-woven fabric is within the above range, appropriate air permeability and barrier properties can be obtained. Further, the obtained spunbonded non-woven fabric has excellent strength.

The nonwoven fabric according to the present disclosure preferably has a basis weight in the range of 5 g / m ² to 50 g / m ² , and more preferably in the range of 10 g / m ² to 25 g / m ² .

The average fiber diameter of the fibers constituting the nonwoven fabric according to the present disclosure is preferably in the range of 5 μm to 30 μm. The upper limit of the average fiber diameter is more preferably 25 μm or less, still more preferably 20 μm or less. In particular, when the average fiber diameter is 20 μm or less, the fibers constituting the nonwoven fabric are sufficiently thin. The lower limit of the average fiber diameter is not particularly limited, but when it is 10 μm or more, an excellent fiber can be obtained.

When the nonwoven fabric according to the present disclosure is a spunbonded nonwoven fabric, the spunbonded nonwoven fabric can be produced by a known method for producing a spunbonded nonwoven fabric, that is, a spunbond method.
Specifically, for example, a resin composition containing fibers constituting a non-woven fabric is spun in advance from a spinning nozzle, the spun long fiber filament is cooled by a cooling fluid or the like, and tension is applied to the filament by drawn air. It can be produced by collecting the obtained filaments on a moving collection belt with a predetermined fineness and forming a spunbonded nonwoven fabric deposited to a predetermined thickness.
Also, if necessary, the deposited web can be entangled. Examples of the entanglement method include a method of heat embossing using an embossing roll, a method of fusing by ultrasonic waves, a method of entwining fibers using a water jet, a method of fusing by hot air through, and a needle punch. Various methods such as the method to be used can be appropriately used.

The nonwoven fabric according to the present disclosure is preferably thermocompression-bonded partially by embossing or the like to improve the strength of the obtained nonwoven fabric and to maintain a balance between flexibility and breathability. When thermocompression bonding is performed by thermocompression bonding, the embossed area ratio (thermocompression bonding portion) is preferably 5% to 30%, more preferably 5% to 20%. Examples of the engraved shape include a circle, an ellipse, an oval, a square, a rhombus, a square, a square, a quilt, a lattice, a hexagonal shell, and a continuous shape based on these shapes.

The nonwoven fabric according to the present disclosure may be used after being subjected to secondary processing such as gear processing, printing, coating, laminating, heat treatment, shaping processing, and pressing processing as long as the object of the present invention is not impaired. The secondary processing can also be applied to a nonwoven fabric laminate containing the spunbonded nonwoven fabric of the present invention.

The nonwoven fabric according to the present disclosure may be imparted with antistatic properties. Examples of the antistatic property-imparting method include a method of applying an appropriate antistatic property-imparting agent such as a fatty acid ester and a quaternary ammonium salt, or a method of mixing with a resin raw material as an additive to form a nonwoven fabric. Be done.
The degree of antistatic property is preferably 1000 V or less (the friction cloth is a cotton cloth) by the method shown in JIS L1094C method (2014) in an atmosphere of 20 ° C. and 40% RH.
The degree of antistatic property is preferably 1000 V or less (the friction cloth is a cotton cloth) by the method shown in JIS L 1094C method (2014) in an atmosphere of 20 ° C. and 40% RH.

The nonwoven fabric according to the present disclosure can be applied to various materials such as sanitary materials, living materials, and general industrial materials. Since the nonwoven fabric according to the present disclosure has excellent hydrophilicity, it is particularly useful as a top sheet, a second sheet or a sheet (core wrap) for absorbent articles such as disposable diapers and sanitary products, and is used for sanitary materials. It can be suitably used for applications such as packaging materials and industrial materials.

Further, the nonwoven fabric according to the present disclosure may be used alone, but it is preferable to use it by laminating it with another material in order to impart other functions. Since the non-woven fabric according to the present disclosure has good post-processability such as heat sealability, it can be used as a living material for oxygen scavengers, cairo, temperature ships, masks, CD (compact disc) bags, food packaging materials, clothes covers, etc. It is applicable to all. For the same reason, the nonwoven fabric according to the present disclosure can be suitably used as an automobile interior material and various backing materials. Further, since it is composed of fine fibers, it can be widely applied as a material for liquid filters and air filters.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

(Example 1)
50 parts by mass of polyoxyethylene (5 mol) stearyl ether as polyoxyalkylene alkyl ether, 25 parts by mass of polyoxyethylene (10 mol) stearylamide as polyoxyalkylene alkylamide, and glycerin monosteer as glycerin monofatty acid ester. The rate was mixed with 25 parts by mass to obtain a surfactant mixture.

Next, 100 parts by mass of a propylene / ethylene random copolymer (melting point (Tm): 142 ° C., MFR: 60 g / 10 min) and polyethylene having a crystallinity of 74.4% (MFR: 16 g / 10 min, molecular weight). Distribution: 11.9) 4 parts by mass and 2 parts by mass of polyethylene-based polymer wax (density: 0.922 g / cm ³ , weight average molecular weight (Mw): 1200, softening point: 113 ° C.), prepared above. Using 8 parts by mass of the surfactant mixture (total mass of the surfactant is 1.6 parts by mass), melt-kneading at 230 ° C. and spinning by the spunbond method, the obtained fibers are collected. After depositing on the surface, spunbonded non-woven fabric (SB) having a fiber diameter of 18 μm and a grain size of 20 g / m ² was obtained by thermal embossing.

[evaluation]
<Hydrophilic>
The obtained spunbonded non-woven fabric was cut into a size of 250 mm × 200 mm and used as a sample. Place 5 sheets of filter paper (No. 2, manufactured by Advantech) on a plate fixed at an angle of 45 degrees with respect to the horizontal direction, place the sample on the filter paper, and place both ends of the sample in the longitudinal direction. It was fixed on the board together with the filter paper. In an environment of 25 ° C, from a height of about 10 mm perpendicular to the sample surface, drop 5.0 ml of artificial urine with a dropper from the drop point of the droplet to the point where the droplet is completely absorbed. Was measured and used as the liquid flow distance (mm).
The liquid flow distance was evaluated based on the following evaluation criteria. The results are shown in Table 1.
As the artificial urine, an aqueous solution of sodium chloride (9 g / liter) having a surface tension of 70 ± 2 mN / m was used.

-Evaluation criteria-
A: The liquid flow distance is less than 50 mm, and the hydrophilicity is excellent.
B: The liquid flow distance is 50 mm or more and less than 80 mm, and the hydrophilicity is slightly excellent.
C: The liquid flow distance is 80 mm or more, and the hydrophilicity is inferior.

<Spinability>
The spinnability was evaluated by measuring the number of yarn breaks for 10 minutes during the above spinning and according to the following classification. The results are shown in Table 1.

-Evaluation criteria-
A: Number of thread breaks 0 to 1 B: Number of thread breaks 2 to 6 C: Number of thread breaks 7 or more

(Examples 2 to 12 and Comparative Examples 1 to 8)
A spunbonded nonwoven fabric (SB) was obtained in the same manner as in Example 1 except that the composition was changed to the blending amounts shown in Tables 1 and 2. Using the obtained spunbonded non-woven fabric, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Details of the abbreviations or components shown in Tables 1 and 2 are as follows. The following crystallinity, weight average molecular weight (Mw), number average molecular weight (Mn), and melt flow rate (MFR) show values obtained by the above-mentioned measuring method.
In addition, in Table 1 and Table 2, "-" indicates that the corresponding component is not contained.

Propene / α-olefin random copolymer 1: Propylene / ethylene random copolymer (melting point: 142 ° C., MFR: 60 g / 10 minutes)
Propene / α-olefin random copolymer 2: Propylene / ethylene random copolymer (melting point: 120 ° C., MFR: 20 g / 10 minutes)
-Propylene homopolymer: melting point: 162 ° C., MFR: 60 g / 10 minutes-PE1: polyethylene having 76.0% crystallinity (MFR: 16 g / 10 minutes, Mw / Mn: 11.9)
-PE2: Polyethylene having a crystallinity of 56.8% (MFR: 38 g / 10 minutes, Mw / Mn: 4.8)
-PE3: Polyethylene having a crystallinity of 69.0% (MFR: 40, crystallinity: 69.0%, Mw / Mn: 9.8)
-PE4: Polyethylene MFR: 25 with a crystallinity of 47.9%, molecular weight distribution 6.4
-PE5: Polyethylene having a crystallinity of 35.6% (MFR: 3.8, Mw / Mn: 2.6)
-Ethylene polymer wax: manufactured by Mitsui Chemicals, Inc., product name "High Wax 110P", density: 0.922 g / cm ³ , weight average molecular weight (Mw): 1200, softening point: 113 ° C.
Polyoxyethylene stearyl ether: polyoxyethylene (5 mol) stearyl ether (polyoxyalkylene alkyl ether represented by the formula (1))
Polyoxyethylene stearylamide: Polyoxyethylene (10 mol) stearylamide (polyoxyalkylene alkylamide represented by the formula (2))
-Glycerin monostearate: Glycerin monofatty acid ester-Polyoxyethylene, polyoxypropylene copolymer: Polymer of polyoxyethylene and polyoxyproprene

From Tables 1 and 2, 100 parts by mass of a propylene / α-olefin random copolymer having a melting point (Tm) in the range of 125 ° C. to 155 ° C. and an ethylene polymer having a crystallinity of 45% to 85%. The surfactant contains 1 part by mass to 10 parts by mass and 0.5 parts by mass to 5 parts by mass of the surfactant, and the surfactant is a non-woven fabric containing fibers containing a polyoxyalkylene alkyl ether, and is the same as the non-woven fabric of the comparative example. In comparison, yarn breakage during spinning was less likely to occur, and the hydrophilicity was excellent.
On the other hand, the non-woven fabric of the comparative example did not satisfy both the difficulty of yarn breakage during spinning and the hydrophilicity.

Based on the above, the nonwoven fabric according to the present disclosure is less likely to cause yarn breakage during spinning and has excellent hydrophilicity. Therefore, disposable diapers, top sheets for absorbent articles such as sanitary products, second sheets, sheets for wrapping absorbers, etc. Can be suitably used as.

Claims (7)

100 parts by mass of a propylene / α-olefin random copolymer having a melting point (Tm) in the range of 125 ° C to 155 ° C.
1 part by mass to 10 parts by mass of an ethylene polymer having a crystallinity of 45% to 85%,
Containing 0.5 parts by mass to 5 parts by mass of a surfactant,
The surfactant comprises a fiber, including a polyoxyalkylene alkyl ether ,
A non-woven fabric in which the surfactant is incorporated inside the fiber . The nonwoven fabric according to claim 1, wherein the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the ethylene polymer is 4.0 or more. The nonwoven fabric according to claim 1 or 2, further comprising an ethylene-based polymer wax having a weight average molecular weight (Mw) of 400 to 15,000. The nonwoven fabric according to any one of claims 1 to 3, wherein the melt flow rate (MFR) of the ethylene polymer is 2 g / 10 minutes to 25 g / 10 minutes. The nonwoven fabric according to any one of claims 1 to 4, wherein the surfactant further contains a polyoxyalkylene alkylamide and a glycerin monofatty acid ester. 30% by mass to 60% by mass of the polyoxyalkylene alkyl ether, 20% by mass to 50% by mass of the polyoxyalkylene alkylamide, and 20% by mass of the glycerin monofatty acid ester with respect to the total mass of the surfactant. The non-woven fabric according to claim 5, which contains ~ 50% by mass. The nonwoven fabric according to any one of claims 1 to 6, which is a spunbonded nonwoven fabric.