Nonwoven fabric and leak-proof sheet for absorbent articles having the same

Abstract

The present invention provides a nonwoven fabric comprising fibers containing a thermoplastic resin having fiber-forming properties and a triglyceride, wherein the thermoplastic resin comprises a polyolefin resin. The triglyceride comprises: (a) a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule, or (b) a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

Description

Technical Field

[0001] The present invention relates to a nonwoven fabric and a leakage-proof sheet for an absorbent article comprising the nonwoven fabric. Background Art

[0002] Nonwoven fabrics are commonly used as barriers to body fluids, such as urine and blood, in absorbent articles like diapers and sanitary napkins, as well as wound dressings and medical gowns. It's well known that the finer the fiber diameter and the smaller the interfiber gaps, the better the barrier properties of nonwoven fabrics. While this method is effective for liquids with relatively high surface tension, it can be less effective for liquids with low surface tension, such as soft stool. To further enhance the barrier properties of nonwoven fabrics, reducing the surface tension of the fibers is effective.

[0003] As a method for reducing surface tension, treating the fiber surface with silicon compounds such as silicone or fluorine compounds is generally known. However, the use of these compounds presents problems in terms of heat resistance, storage stability, and safety for the human body. Adding triglycerides to resins as an alternative to these compounds has also been proposed (see Patent Documents 1 to 4).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: US2012 / 100772A1

[0007] Patent Document 2: US2014 / 272223A1

[0008] Patent Document 3: US2020 / 129345A1

[0009] Patent Document 4: US2019 / 070045A1 Summary of the Invention

[0010] The present invention provides a nonwoven fabric comprising fibers containing a thermoplastic resin having fiber-forming ability and triglyceride.

[0011] It is preferred that the thermoplastic resin include a polyolefin resin.

[0012] Preferably, the above triglycerides include:

[0013] (a) a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule, or

[0014] (b) A triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0015] The present invention also provides a hydrophobizing agent composition for adding to resin, which contains triglyceride.

[0016] Preferably, the above triglycerides include:

[0017] (a) a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule, or

[0018] (b) A triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule. DETAILED DESCRIPTION

[0019] Nonwoven fabrics containing fibers containing triglycerides have the problem that low-surface-tension liquids can seep out of the fabric when exposed to large amounts of them for extended periods. Therefore, the present invention relates to a nonwoven fabric with improved liquid barrier properties compared to conventional nonwoven fabrics.

[0020] Hereinafter, the present invention will be described based on the preferred embodiments of the present invention. The present invention relates to a nonwoven fabric. The nonwoven fabric of the present invention widely includes nonwoven fabrics made by various methods. Regarding the manufacturing method of nonwoven fabrics, various methods such as meltblowing, spunbonding, hot air method, air spinning, hydroentanglement, needle punching, electrospinning, chemical bonding and thermal pressure bonding are known, and the nonwoven fabric of the present invention includes nonwoven fabrics made by these methods. However, it is not limited to these methods, and nonwoven fabrics made by methods other than these methods or nonwoven fabrics made by any combination of these methods are also included in the present invention. As described later, the nonwoven fabric of the present invention has high barrier properties to liquids, so it is particularly advantageous to use a meltblown nonwoven fabric or a composite nonwoven fabric having a meltblown layer as a nonwoven fabric that easily exhibits its properties. As a composite nonwoven fabric having a meltblown layer, for example, a meltblown-spunbond composite nonwoven fabric, a spunbond-meltblown-spunbond composite nonwoven fabric, etc. can be cited.

[0021] When the nonwoven fabric of the present invention is a composite nonwoven fabric comprising at least a spunbond layer and a meltblown layer, the mass ratio of the spunbond layer relative to the total mass of the nonwoven fabric is preferably 50% by mass or more and 95% by mass or less in terms of improving the barrier properties to liquids. From the perspective of further enhancing this advantage, the mass ratio of the spunbond layer relative to the total mass of the nonwoven fabric is more preferably 50% by mass or more and 90% by mass or less, and even more preferably 50% by mass or more and 85% by mass or less.

[0022] On the other hand, from the perspective of improving the barrier properties against liquids, the mass ratio of the meltblown layer relative to the total mass of the nonwoven fabric is preferably 5% by mass or more and 50% by mass or less. From the perspective of making this advantage more pronounced, the mass ratio of the meltblown layer relative to the total mass of the nonwoven fabric is more preferably 10% by mass or more and 50% by mass or less, and even more preferably 15% by mass or more and 50% by mass or less.

[0023] One of the characteristics of the nonwoven fabric of the present invention lies in its constituent fibers. Specifically, the fibers constituting the nonwoven fabric of the present invention comprise a thermoplastic resin having fiber-forming properties and a triglyceride. Various thermoplastic resins having fiber-forming properties are known in the art, but in the present invention, a polyolefin resin is preferably used as the thermoplastic resin from the perspective of obtaining a nonwoven fabric with high liquid barrier properties.

[0024] As the polyolefin resin, for example, homopolymers and copolymers of lower olefins such as ethylene and propylene can be used, and specific examples thereof include polyethylene, polypropylene, and ethylene-α-olefin copolymers.

[0025] Examples of polyethylene include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene.

[0026] As polypropylene, isotactic polypropylene and syndiotactic polypropylene can be cited. In addition, as polypropylene, low stereoregularity homopolypropylene can also be used. Low stereoregularity homopolypropylene refers to the stereoregularity index. 13 Homopolypropylene having an isotactic pentad fraction (mmmm [%]) of 90% or less as measured by C-NMR.

[0027] Examples of the ethylene-α-olefin copolymer include copolymers of α-olefins such as propylene, 1-butene, 1-pentene, and 1-hexene with ethylene. Examples of the copolymer include random copolymers, block copolymers, and graft copolymers. In particular, random copolymers of ethylene and propylene (hereinafter also referred to as "random propylene copolymers") are preferably used.

[0028] From the viewpoint of improving the barrier properties of the nonwoven fabric against liquids, the proportion of ethylene in the random propylene copolymer is preferably from 2 mass% to 70 mass%, more preferably from 4 mass% to 60 mass%, and even more preferably from 6 mass% to 50 mass%.

[0029] Among these polyolefin resins, polypropylene and polyolefins containing propylene as a copolymer component are preferably used from the viewpoint of high fiber forming ability and high liquid barrier properties of the obtained nonwoven fabric.

[0030] Furthermore, the polyolefin resin is preferably a blend of a random propylene copolymer or a low-stereoregular homopolypropylene with a homopolypropylene other than the low-stereoregular homopolypropylene (hereinafter, unless otherwise specified, the homopolypropylene other than the low-stereoregular homopolypropylene will be simply referred to as "homopolypropylene"). In particular, from the viewpoint of high liquid barrier properties of the nonwoven fabric, the polyolefin resin is preferably a blend of a random propylene copolymer and a homopolypropylene.

[0031] The proportion of the random propylene copolymer or the low stereoregular homopolypropylene is preferably 5% by mass or more relative to the fibers constituting the nonwoven fabric of the present invention (when the nonwoven fabric of the present invention has a meltblown nonwoven fabric as described below, it is the fibers constituting the meltblown nonwoven fabric) from the viewpoint of further improving the barrier properties of the nonwoven fabric to liquids. From the viewpoint of further improving the barrier properties, it is more preferably 7% by mass or more, further preferably 9% by mass or more, and even more preferably 15% by mass or more.

[0032] Furthermore, from the viewpoint of improving the spinnability of the fiber, the above ratio is preferably less than 60% by mass, and from the viewpoint of further improving the spinnability, the above ratio is more preferably 45% by mass or less, and even more preferably 30% by mass or less.

[0033] The fibers constituting the nonwoven fabric of the present invention may contain only one type of the above-mentioned polyolefin resins, or two or more types.

[0034] The fibers constituting the nonwoven fabric of the present invention may contain only the above-mentioned polyolefin resin as its constituent resin, or may contain other thermoplastic resins as its constituent resin in addition to the polyolefin resin. In the latter case, it is preferred that the fibers contain 50% by mass or more of the above-mentioned polyolefin resin as the constituent resin.

[0035] Triglyceride, another component contained in the fibers constituting the nonwoven fabric of the present invention, is used to reduce the surface tension of the fibers constituting the nonwoven fabric of the present invention, thereby improving the liquid barrier properties of the nonwoven fabric. The triglyceride may be present adhering to the fiber surface or incorporated into the resin constituting the fibers.

[0036] As triglycerides, triglycerides derived from saturated fatty acids, triglycerides derived from unsaturated fatty acids, and triglycerides derived from both saturated and unsaturated fatty acids can be used. In any case, the number of carbon atoms in the fatty acid can be, for example, 12 to 24. From the perspective of further improving the barrier properties of the nonwoven fabric against liquids, the number of carbon atoms in the fatty acid is preferably 14 to 22, and more preferably 16 to 20.

[0037] The triglyceride may be used alone or as a mixture of a plurality of triglycerides.

[0038] The fibers constituting the nonwoven fabric of the present invention may contain only triglycerides as the glycerides, or may contain monoglycerides and / or diglycerides in addition to triglycerides, as long as the desired effects of the present invention are exhibited. However, from the perspective of improving the liquid barrier properties of the nonwoven fabric of the present invention, it is preferred to use only triglycerides as the glycerides.

[0039] The triglyceride used in the present invention is characterized by having a modified carbon number in the fatty acid residues. Using such a triglyceride can improve the liquid barrier properties of the nonwoven fabric. Specifically, the following (a) or (b) is preferably used as the triglyceride.

[0040] (a) A triglyceride comprising a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0041] (b) A triglyceride comprising a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0042] In the case of (a), two or more triglycerides are used. At least one of the triglycerides contains at least one group derived from a fatty acid having 16 carbon atoms (i.e., a saturated fatty acid or an unsaturated fatty acid) in one molecule (this triglyceride is also referred to as "triglyceride 16"). Triglyceride 16 preferably contains at least one group derived from a fatty acid having 16 carbon atoms in one molecule. Triglyceride 16 may contain one group derived from a fatty acid having 16 carbon atoms in one molecule (this triglyceride is also referred to as "triglyceride P"), two groups (this triglyceride is also referred to as "triglyceride PP"), or three groups (this triglyceride is also referred to as "triglyceride PPP").

[0043] The types of the remaining fatty acid residues in triglyceride P and triglyceride PP are not particularly limited, and may be, for example, residues of saturated or unsaturated fatty acids having 12 to 24 carbon atoms.

[0044] The triglyceride 16 may consist of only triglyceride P, only triglyceride PP, or only triglyceride PPP.

[0045] Triglyceride 16 may also be a combination of two or more selected from triglyceride P, triglyceride PP, and triglyceride PPP. For example, triglyceride 16 may be a combination of triglyceride P and triglyceride PP; a combination of triglyceride P and triglyceride PPP; a combination of triglyceride PP and triglyceride PPP; or a combination of triglyceride P, triglyceride PP, and triglyceride PPP.

[0046] In case (a), at least one of the plurality of triglycerides contains at least one group derived from a fatty acid having 18 carbon atoms (i.e., a saturated fatty acid or an unsaturated fatty acid) in one molecule (this triglyceride is also referred to as "triglyceride 18"). Triglyceride 18 preferably contains at least one group derived from a fatty acid having 18 carbon atoms in one molecule. Triglyceride 18 may contain one group derived from a fatty acid having 18 carbon atoms in one molecule (this triglyceride is also referred to as "triglyceride S"), two groups derived from a fatty acid having 18 carbon atoms in one molecule (this triglyceride is also referred to as "triglyceride SS"), or three groups derived from a fatty acid having 18 carbon atoms in one molecule (this triglyceride is also referred to as "triglyceride SSS").

[0047] The types of the remaining fatty acid residues in triglyceride S and triglyceride SS are not particularly limited, and may be, for example, residues of saturated or unsaturated fatty acids having 12 to 24 carbon atoms.

[0048] The triglyceride 18 may consist of only triglyceride S, only triglyceride SS, or only triglyceride SSS.

[0049] Triglyceride 18 may be a combination of two or more selected from triglyceride S, triglyceride SS, and triglyceride SSS. For example, triglyceride 18 may be a combination of triglyceride S and triglyceride SS; a combination of triglyceride S and triglyceride SSS; a combination of triglyceride SS and triglyceride SSS; or a combination of triglyceride S, triglyceride SS, and triglyceride SSS.

[0050] In the case of (a), the triglyceride may be composed solely of triglyceride 16 and triglyceride 18, or may further contain other triglycerides in addition to triglyceride 16 and triglyceride 18. Examples of the other triglycerides include triglycerides that do not have either a group derived from a fatty acid having 16 carbon atoms or a group derived from a fatty acid having 18 carbon atoms.

[0051] When the group derived from a fatty acid with 16 carbon atoms is represented by "P," the group derived from a fatty acid with 18 carbon atoms is represented by "S," and the other fatty acid-derived groups are represented by "X" and "Y," the combination of fatty acid-derived groups constituting the triglyceride is any one of PPX (i.e., triglyceride PP), SSX (i.e., triglyceride SS), PXY (i.e., triglyceride P), and SXY (i.e., triglyceride S). The structures of the triglycerides represented by PPX, SSX, PXY, and SXY are shown below (A) to (J).

[0052] [Chemical Formula 1]

[0053]

[0054] [Chemical Formula 2]

[0055]

[0056] [Chemical Formula 3]

[0057]

[0058] [Chemical Formula 4]

[0059]

[0060] From the viewpoint of obtaining a nonwoven fabric having higher barrier properties against liquids, it is preferable to use a triglyceride composed only of triglyceride 16 and triglyceride 18.

[0061] In the case of (b), at least one triglyceride can be used. This triglyceride contains at least one group derived from a fatty acid having 16 carbon atoms (i.e., a saturated fatty acid or an unsaturated fatty acid) and at least one group derived from a fatty acid having 18 carbon atoms (i.e., a saturated fatty acid or an unsaturated fatty acid) in one molecule. In particular, from the perspective of obtaining a nonwoven fabric with higher barrier properties to liquids, the triglyceride preferably contains at least one group derived from a saturated fatty acid having 16 carbon atoms and at least one group derived from a saturated fatty acid having 18 carbon atoms in one molecule.

[0062] In case (b), when the group derived from a fatty acid having 16 carbon atoms is represented by "P," the group derived from a fatty acid having 18 carbon atoms is represented by "S," and the other fatty acid-derived groups are represented by "X," the combination of aliphatic groups constituting the triglyceride is any one of SSP, SPP, and SPX. The structure of the triglyceride represented by SPX is any one of (K) to (M) below. The same applies to SSP and SPP.

[0063] [Chemical Formula 5]

[0064]

[0065] In the case of (b), the triglyceride may be composed solely of a triglyceride containing at least one group derived from a fatty acid with a carbon number of 16 and at least one group derived from a fatty acid with a carbon number of 18 in one molecule. Alternatively, the triglyceride may be composed of a triglyceride containing at least one group derived from a fatty acid with a carbon number of 16 and at least one group derived from a fatty acid with a carbon number of 18, and other glycerides. Examples of other triglycerides include triglycerides that do not contain either a group derived from a fatty acid with a carbon number of 16 or a group derived from a fatty acid with a carbon number of 18 in one molecule. From the perspective of obtaining a nonwoven fabric with higher barrier properties to liquids, it is preferred to use only a triglyceride containing at least one group derived from a fatty acid with a carbon number of 16 and at least one group derived from a fatty acid with a carbon number of 18 in one molecule.

[0066] In the present invention, combinations of (a) and (b) may also be used. Specifically, a combination of triglyceride PPP, triglyceride SSS, and SPX may be used. Alternatively, a combination of triglyceride PPP, triglyceride SSS, and SSP may be used; a combination of triglyceride PPP, triglyceride SSS, and SPP may be used. Furthermore, a combination of triglyceride PPX, triglyceride SSX, and triglyceride SPX may be used; a combination of triglyceride PPX, triglyceride SSX, and triglyceride SSP may be used; a combination of triglyceride PPX, triglyceride SSX, and triglyceride SSP may be used; a combination of triglyceride PPX, triglyceride SSX, and triglyceride SPP may be used; a combination of triglyceride PXY, triglyceride SXY, and triglyceride SPX may be used; a combination of triglyceride PXY, triglyceride SXY, and triglyceride SSP may be used; and a combination of triglyceride PXY, triglyceride SXY, and triglyceride SPP may be used.

[0067] In either of the above-mentioned cases (a) and (b), from the perspective of improving the liquid barrier properties of the nonwoven fabric of the present invention, the triglyceride used in the present invention preferably does not contain groups derived from unsaturated fatty acids. "Does not contain groups derived from unsaturated fatty acids" includes both cases where the triglyceride contains no groups derived from unsaturated fatty acids at all and where the triglyceride inevitably contains a small amount of unsaturated fatty acids. "Inevitably containing a small amount of unsaturated fatty acids" means, for example, that the proportion of groups derived from unsaturated fatty acids is 2% by mass or less, based on the total amount of groups derived from fatty acids contained in all triglycerides contained in the fiber.

[0068] In the present invention, from the perspective of further improving the liquid barrier properties of the nonwoven fabric, it is preferred to adjust the ratio of groups derived from fatty acids having 16 carbon atoms and the ratio of groups derived from fatty acids having 18 carbon atoms in all triglycerides contained in the constituent fibers of the nonwoven fabric.

[0069] Regarding the proportion of groups derived from fatty acids having 16 carbon atoms, from the viewpoint of further improving the barrier properties of the nonwoven fabric to liquids, the proportion is preferably 1% by mass or more based on the total amount of groups derived from fatty acids in all triglycerides contained in the constituent fibers of the nonwoven fabric. From the viewpoint of further improving the barrier properties, it is more preferably 10% by mass or more, further preferably 15% by mass or more, still further preferably 20% by mass or more, and particularly preferably 25% by mass or more.

[0070] In addition, from the viewpoint of further improving the barrier properties of the nonwoven fabric to liquids, the above ratio is preferably less than 55% by mass. From the viewpoint of further improving the barrier properties, the above ratio is more preferably 50% by mass or less, and even more preferably 45% by mass or less.

[0071] The above ratio is preferably 1% by mass or more and less than 55% by mass, more preferably 10% by mass or more and less than 55% by mass, further preferably 15% by mass or more and less than 55% by mass, still further preferably 20% by mass or more and less than 50% by mass, and particularly preferably 25% by mass or more and less than 45% by mass.

[0072] Regarding the proportion of groups derived from fatty acids having 18 carbon atoms, from the perspective of further improving the barrier properties of the nonwoven fabric against liquids, the proportion is preferably 5% by mass or more, based on the total amount of groups derived from fatty acids in all triglycerides contained in the constituent fibers of the nonwoven fabric, more preferably 35% by mass or more, even more preferably 45% by mass or more, still more preferably 50% by mass or more, and particularly preferably 55% by mass or more.

[0073] In addition, from the perspective of further improving the barrier properties of the nonwoven fabric to liquids, the above ratio is preferably less than 90% by mass. From the perspective of further improving the barrier properties, the above ratio is more preferably 70% by mass or less, and even more preferably 65% ​​by mass or less.

[0074] The above ratio is preferably 5% by mass or more and less than 90% by mass, more preferably 35% by mass or more and less than 90% by mass, further preferably 45% by mass or more and less than 90% by mass, still further preferably 50% by mass or more and less than 70% by mass, and further preferably 55% by mass or more and less than 65% by mass.

[0075] Regarding the ratio of groups derived from fatty acids with 16 carbon atoms to groups derived from fatty acids with 18 carbon atoms, in order to further improve the barrier properties of the nonwoven fabric against liquids, the mass ratio of groups derived from fatty acids with 18 carbon atoms to groups derived from fatty acids with 16 carbon atoms (C18 / C16) contained in all triglycerides contained in the fiber is preferably 1.0 or more and 15.0 or less. In order to further enhance this advantage, the mass ratio of groups derived from fatty acids with 18 carbon atoms to groups derived from fatty acids with 16 carbon atoms (C18 / C16) is more preferably 1.2 or more and 10.0 or less, further preferably 1.3 or more and 5.0 or less, and even more preferably 1.3 or more and 2.7 or less.

[0076] The ratios of the groups derived from fatty acids having 16 carbon atoms and the groups derived from fatty acids having 18 carbon atoms, based on the total amount of the groups derived from fatty acids in all triglycerides contained in the fiber, were measured by the following method.

[0077] Using a good solvent for triglycerides, such as toluene, triglycerides present on the surfaces of the fibers constituting the nonwoven fabric are extracted.

[0078] The ester bonds in the extracted triglycerides are hydrolyzed with an alkali to form methyl esters, and the methyl esterified fatty acids are quantitatively analyzed by gas chromatography.

[0079] It should be noted that TOF-MS (time-of-flight mass spectrometry) can be used to determine whether a molecule of triglyceride contains alkyl chains with different carbon numbers. In detail, the molecular weight distribution of triglycerides is measured by TOF-MS, and whether the molecule contains alkyl chains with different carbon numbers is determined based on the molecular weight of a molecule. Whether a molecule of a compound with the same molecular weight contains alkyl chains with different carbon numbers can be determined by a tandem mass spectrometer (MS / MS) as a mass spectrometer. A first mass separation unit is used to select specific ions, which collide with an inert gas to produce fragment ions, and a second mass separation unit is used to separate and detect the above-mentioned fragment ions, thereby performing the judgment.

[0080] In the nonwoven fabric of the present invention, the triglyceride satisfying the above-mentioned (a) and / or the triglyceride satisfying (b) is preferably contained in an amount of 1% by mass or more relative to the fiber containing the triglyceride, from the viewpoint of further improving the barrier property of the nonwoven fabric to liquids, and is preferably contained in an amount of 5% by mass or more, and more preferably contained in an amount of 9% by mass or more, from the viewpoint of further improving the barrier property.

[0081] From the perspective of improving spinnability and improving the texture of the nonwoven fabric, the ratio of the triglyceride to the triglyceride-containing fiber is preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 15% by mass or less, and even more preferably 14% by mass or less.

[0082] The ratio of the above-mentioned triglycerides to the triglyceride-containing fiber is preferably 1% by mass or more and less than 30% by mass, more preferably 5% by mass or more and 20% by mass or less, further preferably 9% by mass or more and 15% by mass or less, and still more preferably 9% by mass or more and 14% by mass or less.

[0083] One example of a method for incorporating triglyceride into the fibers constituting a nonwoven fabric is to melt-knead the thermoplastic resin constituting the fibers with triglyceride, thereby incorporating the triglyceride into the thermoplastic resin. Specifically, the present invention provides a nonwoven fabric comprising fibers obtained by spinning a melt obtained by melt-kneading the thermoplastic resin and triglyceride. However, the method for producing the nonwoven fabric of the present invention is not limited to this method; triglyceride may also be incorporated into the fibers by other methods.

[0084] The fibers constituting the nonwoven fabric preferably have a relaxation time of 10 μs (microseconds) or more as measured by pulsed NMR. In fibers with such a relaxation time, triglycerides easily seep out from the inside of the fibers, so the nonwoven fabric containing such fibers has a high barrier property to liquids. In order to improve the exudation, a method of changing the crystallinity is generally used, but on the other hand, the following phenomenon has been confirmed: even if the crystallinity is the same, there is a difference in exudation. The inventors have conducted in-depth research and the results clearly show that as a factor affecting exudation, in addition to crystallinity, relaxation time is also important. From the perspective of making this advantage more obvious, the above relaxation time is more preferably 12 μs or more, further preferably 15 μs or more, and further preferably 20 μs or more. From the perspective of promoting the exudation of triglycerides, the longer the above relaxation time, the more ideal it is. Therefore, there is no upper limit to the above relaxation time, but if the relaxation time is as long as about 80 μs, the expected effect of the present invention can be fully exerted.

[0085] It should be noted that in the present invention, even if the ratio of triglyceride contained in the fiber is small, the barrier property of the nonwoven fabric to liquids can be improved, and therefore adverse effects due to the leakage of triglyceride are less likely to occur.

[0086] In order to set the relaxation time of pulse NMR within the above range, for example, a random propylene copolymer or a homopolypropylene with low stereoregularity may be blended and used.

[0087] The crystallinity and the relaxation time of pulsed NMR were measured by the method described in Examples below.

[0088] From the viewpoint of improving the liquid barrier properties of the nonwoven fabric, the thickness of the fibers constituting the nonwoven fabric of the present invention is preferably 40 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less.

[0089] The thinner the fiber, the higher the barrier property to liquids. However, this may make it difficult to produce nonwoven fabrics or reduce the production efficiency of nonwoven fabrics. Therefore, the actual lower limit is preferably 0.1 μm or more, more preferably 0.3 μm or more, and even more preferably 0.5 μm or more.

[0090] Regarding the thickness of the fibers, a small sample was collected from the nonwoven fabric, and 70 fibers randomly selected were used as objects. The fiber diameters were directly measured using a scanning electron microscope, and the average value (to two significant figures) was calculated.

[0091] From the viewpoint of improving the barrier properties of the nonwoven fabric to liquids, the nonwoven fabric of the present invention preferably has a weight per unit area of ​​0.2 g / m 2 More than 0.6 g / m 2 More preferably, 1.0 g / m 2 above.

[0092] The larger the value of the unit area weight, the higher the barrier property to liquids, but there is a case where the texture is reduced or the economic efficiency is reduced. Therefore, the actual upper limit is preferably 50g / m 2 Below, more preferably 35g / m 2 Below, more preferably 20g / m 2 the following.

[0093] The basis weight of a nonwoven fabric is the value obtained by dividing the weight of the nonwoven fabric by the area of ​​the nonwoven fabric. 2 The basis weight is calculated using samples of the above area. In consideration of the texture of the nonwoven fabric, it is more preferable to measure three or more samples of one type and take the average value as the basis weight of the sample.

[0094] The nonwoven fabric of the present invention may be composed solely of fibers containing a polyolefin resin and the above-mentioned triglyceride, or may be composed of the fibers and other fibers. In the latter case, the nonwoven fabric of the present invention may comprise a blend of the fibers and other fibers, or may comprise a laminate of a layer containing only the fibers and a layer containing only other fibers. For example, the nonwoven fabric may be composed of a laminate of a meltblown layer containing only the fibers and a spunbond layer containing only other fibers disposed on each surface of the meltblown layer.

[0095] In particular, the nonwoven fabric of the present invention comprises a meltblown layer and a spunbond layer. From the perspective of improving barrier properties to liquids, particularly from the perspective of effectively suppressing the leakage of liquids under pressure, the meltblown layer is preferably composed of fibers containing a random propylene copolymer or low-stereoregularity homopolypropylene, homopolypropylene, and the aforementioned triglyceride. On the other hand, since the contribution of the spunbond layer to barrier properties is minimal, its constituent fibers do not need to contain the aforementioned triglyceride; the spunbond layer can be composed of fibers that do not contain the triglyceride.

[0096] When the nonwoven fabric of the present invention comprises this fiber and other fibers, regardless of the form of the nonwoven fabric, from the viewpoint of improving the barrier properties of the nonwoven fabric to liquids, especially from the viewpoint of improving the resistance to liquid seepage under pressure, the proportion of the fibers in the nonwoven fabric is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. In addition, it is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

[0097] The nonwoven fabric of the present invention has high barrier properties against liquids, particularly water, and is therefore suitable for applications requiring waterproofness. For example, the nonwoven fabric of the present invention can be used in back sheets for absorbent articles such as disposable diapers and sanitary napkins, leak-proof sheets for cuffs and wings, waterproof sheets for rain gear, bandages, wound dressings, medical isolation gowns, surgical gowns, surgical diapers and covers, and surgical caps.

[0098] When the nonwoven fabric of the present invention is used as a leakage-barrier sheet for absorbent articles, the nonwoven fabric itself may be used as the leakage-barrier sheet, or the nonwoven fabric may be used in combination with other sheet materials.

[0099] In one embodiment, the nonwoven fabric of the present invention can be used as a filter medium for various fluids or a portion thereof. In addition, the nonwoven fabric of the present invention can be used as a filter for masks and the like.

[0100] The above description relates to a nonwoven fabric comprising fibers containing a specific triglyceride. The present invention also provides a hydrophobic agent composition for resin addition containing the specific triglyceride. This hydrophobic agent composition is used to impart hydrophobicity to a molded article formed from the resin by kneading it into a molten resin. The hydrophobic agent composition comprises a triglyceride, and the triglyceride comprises the following (a) or (b).

[0101] (a) A mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0102] (b) A triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0103] In one embodiment, the hydrophobizing agent composition of the present invention is intended to be contained within fibers to impart hydrophobicity to the fibers.

[0104] Specifically, in a molded article such as a fiber or film containing a resin to which the hydrophobizing agent composition for internal resin addition of the present invention is added, even if the hydrophobizing agent composition present on the surface of the molded article is removed due to friction or the like, the hydrophobizing agent composition seeps out from the interior of the molded article to the surface, thereby restoring the desired hydrophobicity. This allows the hydrophobicity of the molded article surface to be maintained for a long period of time. In particular, when the resin constituting the molded article is a polyolefin resin comprising a random propylene copolymer, a homopolypropylene with low stereoregularity, and a homopolypropylene, and particularly when the resin constituting the molded article is a polyolefin resin comprising a random propylene copolymer and a homopolypropylene, the hydrophobicity of the molded article is more reliably maintained due to the more reliably seeping out of the hydrophobizing agent composition.

[0105] In addition, in other embodiments, the hydrophobic composition of the present invention is used to be added to resins constituting rain gear, bandages, wound dressing materials, medical isolation gowns, surgical gowns, surgical abdominal cloths and covers, surgical gowns, surgical caps, artificial leather, synthetic leather, suede, umbrellas, tents, outdoor clothing, etc., to impart hydrophobicity to these.

[0106] In particular, the hydrophobic agent composition of the present invention is preferably used for fibers comprising a thermoplastic resin having fiber-forming properties, and is particularly preferably used for fibers wherein the thermoplastic resin comprises a polyolefin resin. In particular, as described above, it is preferred that the polyolefin resin comprises a random propylene copolymer, a homopolypropylene with low stereoregularity, or a homopolypropylene, and particularly preferably a random propylene copolymer and a homopolypropylene, because the hydrophobic agent composition more reliably bleeds out.

[0107] It should be noted that the details of the triglyceride contained in the hydrophobizing agent composition of the present invention are the same as those of the triglyceride contained in the nonwoven fabric of the present invention, and the description of the triglyceride contained in the nonwoven fabric can also be applied as appropriate.

[0108] Regarding the above-mentioned embodiment, the present invention further discloses the following nonwoven fabric.

[0109] <1>

[0110] A nonwoven fabric comprising fibers, wherein the fibers contain a thermoplastic resin having fiber-forming ability and triglyceride.

[0111] The above-mentioned thermoplastic resin includes a polyolefin resin,

[0112] These triglycerides include:

[0113] (a) a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule, or

[0114] (b) A triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0115] <2>

[0116] The nonwoven fabric according to the above <1>, wherein the triglyceride does not include a group derived from an unsaturated fatty acid.

[0117] <3>

[0118] The nonwoven fabric according to the above <1> or <2>, wherein the triglyceride contains at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0119] <4>

[0120] The nonwoven fabric according to the above <3>, wherein the triglyceride contains at least a group derived from a saturated fatty acid having 16 carbon atoms and a group derived from a saturated fatty acid having 18 carbon atoms in one molecule.

[0121] <5>

[0122] The nonwoven fabric according to any one of <1> to <4>, wherein, based on the total amount of the groups derived from fatty acids contained in all the triglycerides contained in the fibers, the proportion of the groups derived from fatty acids having 16 carbon atoms is 1% by mass or more and less than 55% by mass, and the proportion of the groups derived from fatty acids having 18 carbon atoms is 5% by mass or more and less than 90% by mass.

[0123] <6>

[0124] The nonwoven fabric as described in any one of <1> to <5> above, wherein, based on the total amount of groups derived from fatty acids contained in all the above triglycerides contained in the above fibers, the proportion of groups derived from fatty acids having 16 carbon atoms is 10% by mass or more and less than 55% by mass, and the proportion of groups derived from fatty acids having 18 carbon atoms is 45% by mass or more and less than 90% by mass.

[0125] <7>

[0126] The nonwoven fabric as described in any one of <1> to <6> above, wherein, based on the total amount of groups derived from fatty acids contained in all the above triglycerides contained in the above fibers, the proportion of groups derived from fatty acids having 16 carbon atoms is 20% by mass or more and 50% by mass or less, and the proportion of groups derived from fatty acids having 18 carbon atoms is 50% by mass or more and 70% by mass or less.

[0127] <8>

[0128] The nonwoven fabric as described in any one of <1> to <7> above, wherein, based on the total amount of groups derived from fatty acids contained in all the above triglycerides contained in the above fibers, the proportion of groups derived from fatty acids having 16 carbon atoms is 25% by mass or more and 45% by mass or less, and the proportion of groups derived from fatty acids having 18 carbon atoms is 55% by mass or more and 65% by mass or less.

[0129] <9>

[0130] The nonwoven fabric according to any one of <1> to <8>, wherein the triglyceride consists solely of the following substances:

[0131] (a) a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule, or

[0132] (b) A triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0133] <10>

[0134] The nonwoven fabric according to any one of <1> to <9>, wherein the mass ratio of the groups derived from fatty acids having 18 carbon atoms to the groups derived from fatty acids having 16 carbon atoms contained in all the triglycerides contained in the fibers is 1.0 to 15.0.

[0135] <11>

[0136] The nonwoven fabric according to any one of <1> to <10>, wherein the mass ratio of the groups derived from fatty acids having 18 carbon atoms to the groups derived from fatty acids having 16 carbon atoms contained in all the triglycerides contained in the fibers is 1.3 or more and 5.0 or less.

[0137] <12>

[0138] The nonwoven fabric according to any one of <1> to <11>, wherein the relaxation time of the fiber measured by pulsed NMR is 10 μs or longer.

[0139] <13>

[0140] The nonwoven fabric according to any one of <1> to <12>, wherein the fiber diameter of the fibers is 0.1 μm or more and 40 μm or less.

[0141] <14>

[0142] The nonwoven fabric according to any one of <1> to <13>, having a weight per unit area of ​​0.2 g / m 2 Above and 50g / m 2 the following.

[0143] <15>

[0144] The nonwoven fabric according to any one of <1> to <14>, which is a meltblown nonwoven fabric or a composite nonwoven fabric having a meltblown layer.

[0145] <16>

[0146] The nonwoven fabric according to any one of <1> to <15>, wherein the nonwoven fabric comprises at least a spunbond layer and a meltblown layer.

[0147] The mass ratio of the spunbond layer to the total mass of the nonwoven fabric is 50 mass% or more and 95 mass% or less,

[0148] The mass ratio of the meltblown layer to the total mass of the nonwoven fabric is 5 mass % or more and 50 mass % or less.

[0149] <17>

[0150] The nonwoven fabric according to any one of <1> to <16>, wherein the polyolefin resin is polypropylene.

[0151] <18>

[0152] The nonwoven fabric according to any one of <1> to <17>, wherein the triglyceride is contained in an amount of 1% by mass to 30% by mass based on the fibers containing the triglyceride.

[0153] <19>

[0154] The nonwoven fabric according to the above <18>, wherein the triglyceride is contained in an amount of 9% by mass to 14% by mass based on the fibers containing the triglyceride.

[0155] <20>

[0156] The nonwoven fabric according to any one of <1> to <19>, wherein the ratio of the fibers containing the triglyceride in the nonwoven fabric is 3% by mass or more.

[0157] <21>

[0158] The nonwoven fabric according to any one of <1> to <20>, wherein the polyolefin resin comprises a random propylene copolymer or a low stereoregular homopolypropylene, and a homopolypropylene.

[0159] <22>

[0160] The nonwoven fabric according to the above <21>, wherein the ratio of the random propylene copolymer or the low-stereoregularity homopolypropylene to the fibers is 5% by mass or more and less than 60% by mass.

[0161] <23>

[0162] The nonwoven fabric according to the above <22>, wherein the ratio of the random propylene copolymer or the low-stereoregularity homopolypropylene to the fibers is 9% by mass or more and less than 30% by mass.

[0163] <24>

[0164] The nonwoven fabric according to any one of <1> to <23>, comprising a meltblown layer and a spunbond layer.

[0165] The meltblown layer includes fibers containing a random propylene copolymer or low stereoregularity homopolypropylene, homopolypropylene, and the triglyceride.

[0166] <25>

[0167] The nonwoven fabric according to the above <1>, wherein the polyolefin resin comprises a random propylene copolymer or a low stereoregular homopolypropylene, and a homopolypropylene.

[0168] Based on the total amount of groups derived from fatty acids contained in all the above-mentioned triglycerides contained in the above-mentioned fibers, the proportion of groups derived from fatty acids with 16 carbon atoms is greater than 20 mass% and less than 50 mass%, and the proportion of groups derived from fatty acids with 18 carbon atoms is greater than 50 mass% and less than 70 mass%.

[0169] <26>

[0170] The nonwoven fabric according to the above <1>, wherein the polyolefin resin comprises a random propylene copolymer or a low stereoregular homopolypropylene, and a homopolypropylene.

[0171] The triglyceride mentioned above is extremely hardened palm oil.

[0172] <27>

[0173] The nonwoven fabric according to <26>, wherein the ratio of the random propylene copolymer or the low-stereoregularity homopolypropylene to the fibers is 5% by mass or more and less than 60% by mass,

[0174] The content of the triglyceride is 1% by mass or more and 30% by mass or less relative to the fiber containing the triglyceride.

[0175] <28>

[0176] The nonwoven fabric according to <26> or <27>, wherein the content of the triglyceride is 9% by mass or more and 14% by mass or less based on the fiber containing the triglyceride.

[0177] <29>

[0178] The nonwoven fabric according to the above <26> or <27>, wherein the ratio of the random propylene copolymer or the low-stereoregularity homopolypropylene to the fibers is 9% by mass or more and less than 30% by mass.

[0179] <30>

[0180] The nonwoven fabric according to the above <26>, wherein the polyolefin resin comprises the random propylene copolymer and the homopolypropylene.

[0181] The ratio of the random propylene copolymer to the fiber is 5% by mass or more and less than 60% by mass,

[0182] The content of the triglyceride is 1% by mass or more and 30% by mass or less relative to the fiber containing the triglyceride.

[0183] <31>

[0184] The nonwoven fabric as described in <28> or <29> above, comprising a meltblown layer and a spunbond layer,

[0185] The meltblown layer includes fibers, and the fibers include the random propylene copolymer or the low-stereoregularity homopolypropylene, the homopolypropylene, and the triglyceride.

[0186] <32>

[0187] The nonwoven fabric according to the above <31>, wherein the meltblown layer comprises fibers containing the random propylene copolymer, the homopolypropylene, and the triglyceride.

[0188] <33>

[0189] A nonwoven fabric comprises fibers obtained by spinning a melt obtained by melt-kneading a thermoplastic resin and triglyceride.

[0190] <34>

[0191] A leakage-proof sheet for absorbent articles, comprising the nonwoven fabric according to any one of <1> to <33> above.

[0192] <35>

[0193] An absorbent article comprising the nonwoven fabric according to any one of <1> to <33> above.

[0194] <36>

[0195] A hydrophobic agent composition for resin addition, comprising triglyceride,

[0196] These triglycerides include:

[0197] (a) a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule, or

[0198] (b) A triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0199] <37>

[0200] The hydrophobizing agent composition for adding to a resin as described in the above <36>, wherein the triglyceride does not contain a group derived from an unsaturated fatty acid.

[0201] <38>

[0202] The hydrophobizing agent composition for adding to a resin as described in <36> or <37>, wherein the triglyceride contains at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0203] <39>

[0204] The hydrophobic agent composition for adding to a resin as described in any one of <36> to <38> above, wherein, based on the total amount of groups derived from fatty acids contained in the triglyceride, the proportion of groups derived from fatty acids having 16 carbon atoms is 10% by mass or more and less than 55% by mass, and the proportion of groups derived from fatty acids having 18 carbon atoms is 45% by mass or more and less than 90% by mass.

[0205] <40>

[0206] The hydrophobic agent composition for internal addition to a resin as described in any one of <36> to <39> is internally added to a polyolefin resin containing a random propylene copolymer or a homopolypropylene with low stereoregularity, and a homopolypropylene.

[0207] <41>

[0208] The hydrophobizing agent composition for internal addition to a resin as described in any one of <36> to <40> is internally added to a polyolefin resin containing a random propylene copolymer and homopolypropylene.

[0209] <42>

[0210] A composition containing triglycerides is used as a hydrophobic agent composition for resin addition.

[0211] These triglycerides include:

[0212] (a) a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule, or

[0213] (b) A triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0214] <43>

[0215] The use as described in the above <42>, wherein the triglyceride does not contain a group derived from an unsaturated fatty acid.

[0216] <44>

[0217] The use according to the above <42> or <43>, wherein the triglyceride contains at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

[0218] <45>

[0219] The use as described in any one of <42> to <44> above, wherein, based on the total amount of groups derived from fatty acids contained in the above triglycerides, the proportion of groups derived from fatty acids with 16 carbon atoms is 10% by mass or more and less than 55% by mass, and the proportion of groups derived from fatty acids with 18 carbon atoms is 45% by mass or more and less than 90% by mass.

[0220] <46>

[0221] The use as described in any one of <42> to <45> above, wherein the polyolefin resin is internally added to a polyolefin resin comprising a random propylene copolymer or a homopolypropylene with low stereoregularity, and a homopolypropylene.

[0222] <47>

[0223] The use as described in any one of <42> to <46> above, wherein the polyolefin resin is internally added to the polyolefin resin comprising the random propylene copolymer and the homopolypropylene.

[0224] Example

[0225] Hereinafter, the present invention will be described in more detail by way of examples. However, the scope of the present invention is not limited by these examples. Unless otherwise specified, "%" means "mass %".

[0226] [Example 1-1]

[0227] In this example, the hydrophobicity of a triglyceride-containing hydrophobic agent composition was evaluated using the following method on a triglyceride-containing membrane. The results are shown in Table 1 below.

[0228] (1) Resin production

[0229] A propylene homopolymer (HP461Y manufactured by LyondellBasell, hereinafter referred to as "homo-PP"), a random propylene copolymer (Vistamaxx 8880 manufactured by Exxonmobil, hereinafter referred to as "random PP"), and triglyceride were weighed to a mass ratio of 63 / 27 / 10. These materials were placed in a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) and kneaded at 180°C and 30 rpm for 10 minutes. After kneading, a resin mass was recovered. The ethylene content in the random PP was 8%.

[0230] The triglyceride used was a mixture of palmitic acid triglyceride and stearic acid triglyceride. The mixing ratio is shown in Table 1 below.

[0231] (2) Film production

[0232] The resin block was pressed at 180°C and 100 kgf for 1 minute using a Labo Press (manufactured by Toyo Seiki Co., Ltd.), and then cooled and pressed at room temperature and 100 kgf for 1 minute to produce a film. The film thickness was adjusted to 0.5 mm by inserting a 0.5 mm spacer.

[0233] (3) Evaluation of hydrophobicity

[0234] The prepared membrane was immersed in 50 mL of toluene solution and then cleaned by wiping the membrane surface with toilet paper. The cleaned membrane was placed in an electric dryer and stored at 40°C for 7 days. After storage, the contact angle of the membrane surface was measured using a contact angle meter (Drop Master 500, manufactured by Kyowa Interface Science).

[0235] ·Determination method: drop method

[0236] Evaluation liquid: Wetting tension test liquid (surface tension at 25°C: 35.0 mN / m, manufactured by Kanto Chemical)

[0237] Droplet volume: 2μL

[0238] For each test piece, the contact angle was measured at five locations after contact with a drop of liquid for 10 seconds, and the average value of the five drops was taken as the contact angle value.

[0239] [Examples 1-2]

[0240] Palmitic acid triglyceride and stearic acid triglyceride were used at the mixing ratio shown in Table 1. A film was produced in the same manner as in Example 1-1 except for this, and its hydrophobicity was evaluated.

[0241] [Examples 1-3]

[0242] Extremely hardened palm oil (manufactured by Ueda Oil Co., Ltd.) was used as the triglyceride. A membrane was produced and its hydrophobicity evaluated in the same manner as in Example 1-1. The triglyceride was a mixture of multiple triglycerides, and the carbon number distribution of the fatty acid-derived groups in the triglyceride is shown in Table 1.

[0243] [Examples 1-4]

[0244] Technical grade tristearin (Sigma-Aldrich) was used as the triglyceride. The ratio of the groups derived from fatty acids having 16 carbon atoms to the groups derived from fatty acids having 18 carbon atoms in the triglyceride is shown in Table 1. A membrane was prepared in the same manner as in Example 1-1, and its hydrophobicity was evaluated.

[0245] [Examples 1-5]

[0246] Hardened high-erucic acid rapeseed oil (manufactured by Yokoseki Oil & Fats Co., Ltd.) was used as the triglyceride. A membrane was produced and its hydrophobicity evaluated in the same manner as in Example 1-1. The triglyceride was a mixture of multiple triglycerides, and the carbon number distribution of the fatty acid-derived groups in the triglyceride is shown in Table 1.

[0247] [Comparative Example 1-1]

[0248] Palmitic acid triglyceride was used as the triglyceride. A membrane was produced in the same manner as in Example 1-1 except for this, and its hydrophobicity was evaluated.

[0249] [Comparative Example 1-2]

[0250] Stearic acid triglyceride was used as the triglyceride. A film was produced in the same manner as in Example 1-1 except for the above, and its hydrophobicity was evaluated.

[0251] [Table 1]

[0252]

[0253] As is clear from the results shown in Table 1, the contact angle of the film of each Example with the evaluation liquid is higher than that of the film of the comparative example.

[0254] [Example 2-1]

[0255] (1) Manufacturing of masterbatch

[0256] These materials were weighed so that the mass ratio of homopoly PP to triglyceride became 90 / 10, and were put into a twin-screw extruder (manufactured by Toyo Seiki Co., Ltd.) and kneaded to prepare a masterbatch.

[0257] The triglycerides used were the same as those used in Examples 1-3.

[0258] (2) Manufacturing of meltblown nonwoven fabrics

[0259] The obtained masterbatch is used as a raw material to manufacture meltblown nonwoven fabrics.

[0260] The weight per unit area of ​​the obtained meltblown nonwoven fabric and the fiber diameters of the constituent fibers are shown in Table 2.

[0261] The basis weight of the meltblown nonwoven fabric was determined by measuring the mass of ten 16 cm x 16 cm pieces randomly collected from the nonwoven fabric. The average of the measured masses was divided by 0.0256 to obtain the value obtained by dividing the average by 0.0256.

[0262] The spunbond nonwoven fabrics shown in Table 2 were stacked on each surface of the meltblown nonwoven fabric obtained in this manner to obtain an SMS nonwoven fabric.

[0263] [Examples 2-2 to 2-12]

[0264] Homopolymer PP and random PP were used as polyolefin resins. The ratios of homopolymer PP, random PP, and triglyceride are shown in Tables 2 and 3.

[0265] For Examples 2-6, the same triglycerides as used in Examples 1-4 were used.

[0266] For Examples 2-7, the same triglycerides as used in Examples 1-5 were used.

[0267] For Examples 2-8, extremely hardened soybean oil was used as the triglyceride.

[0268] Except for this, an SMS nonwoven fabric was produced in the same manner as in Example 2-1.

[0269] [Comparative Example 2-1]

[0270] Homopolymer PP and random PP were used as polyolefin resins. Triglyceride was not used. The ratio of homopolymer PP to random PP is shown in Table 3. SMS nonwoven fabric was produced in the same manner as in Example 2-1 except for these differences.

[0271] [Evaluation 1]

[0272] The meltblown layers of the SMS nonwoven fabrics obtained in Examples 2-1, 2-4, 2-6, and 2-7, and Comparative Example 2-1, were subjected to pulsed NMR relaxation time measurements using the following method. The results are shown in Table 2 below.

[0273] Device used: the minispec mq20 manufactured by Bruker

[0274] ·Measurement method: Solid-echo method

[0275] 90° pulse width: 2.1 microseconds

[0276] Repeat time: 1 second

[0277] ·Cumulative number of times: 32 times

[0278] Measurement temperature: 30°C

[0279] ·Analysis method: nonlinear least squares method

[0280] Place the sample into the sample tube and measure 1 T2 relaxation time of H. For the relaxation time peak obtained from the sample measurement, the waveforms of components with different relaxation times are separated and detected into two components: a component with a short relaxation time (S) and a component with a long relaxation time (L). The proton ratios H(S) [%] and H(L) [%] of each component, as well as the relaxation times T2(S) and T2(L) are determined. The measurement is repeated four times, and the average value is used as the measurement result. Using the measured proton ratios and relaxation times of the two components, the relaxation time of each sample is calculated according to the following formula.

[0281] Relaxation time [microseconds] = {<H(S)÷100>×T2(S)}+{<H(L)÷100>×T2(L)}

[0282] [Evaluation 2]

[0283] The SMS nonwoven fabrics obtained in Examples and Comparative Examples were evaluated for liquid seepage by the following method. The results are shown in Tables 2 and 3 below.

[0284] An SMS nonwoven fabric cut into 8 cm × 8 cm was placed on a filter paper (Advantec Toyo Co., Ltd., No. 2, diameter 70 mm). A dry pulp sheet cut into 8 cm × 8 cm (LION Co., Ltd., Reed Healthy Cooking Paper Double (trade name), weight per unit area 40 g / m2) was placed on a filter paper (Advantec Toyo Co., Ltd., No. 2, diameter 70 mm). 2 ) is placed on the non-woven fabric.

[0285] 1 g of wetting tension test liquid (surface tension at 25°C: 35.0 mN / m) was injected into the center of the dry pulp sheet through a dropper. After injection, a 60 mm diameter acrylic plate was stacked, a weight was placed on it, and pressure was applied at 7 kPa for 1 hour.

[0286] After 1 hour, the weight was removed and the area of ​​the liquid seeping onto the filter paper was measured using an image analyzer. The measurement was performed twice, and the total area of ​​the liquid seeping onto the filter paper was taken as the seepage area of ​​each sample.

[0287] [Table 2]

[0288]

[0289] [Table 3]

[0290]

[0291] As is clear from the results shown in Tables 2 and 3, the SMS nonwoven fabrics obtained in the respective Examples have improved barrier properties against liquids having low surface tension by adding a small amount of triglyceride.

[0292] In particular, a comparison between Example 2-1 and Examples 2-2 to 2-5 clearly demonstrates that the use of a combination of homo-PP and random PP as the polyolefin resin constituting the meltblown nonwoven fabric improves barrier properties against liquids with low surface tension, compared to the case of using homo-PP alone. In particular, it was found that the incorporation of random PP in a mass ratio of 15% to 30% by mass relative to the fibers constituting the meltblown nonwoven fabric significantly enhances barrier properties against liquids with low surface tension.

[0293] Furthermore, Examples 2-9 to 2-12 clearly demonstrate that the blending of 8% to 18% by mass of triglyceride into the fibers constituting the meltblown nonwoven fabric improves barrier properties against liquids with low surface tension. In particular, blending of 9% to 14% by mass of triglyceride significantly enhances barrier properties against liquids with low surface tension.

[0294] Furthermore, from the results shown in Examples 2-1 and 2-4, it can be seen that even when the type of triglyceride is the same, the barrier properties of the nonwoven fabric are improved by extending the relaxation time of the fiber.

[0295] In addition, from the comparison between Example 2-4 and Examples 2-6 to 2-8, it can be seen that by combining triglycerides in which the proportion of groups derived from fatty acids with a carbon number of 16 is greater than 20 mass% and less than 50 mass%, and the proportion of groups derived from fatty acids with a carbon number of 18 is greater than 50 mass% and less than 70 mass%, based on the total amount of groups derived from fatty acids contained in the triglycerides, the barrier properties to liquids with low surface tension are greatly improved.

[0296] Industrial applicability

[0297] As described above in detail, according to the present invention, a nonwoven fabric having higher liquid barrier properties than ever before is provided.

Claims

1. A nonwoven fabric comprising fibers containing a thermoplastic resin having fiber-forming ability and triglyceride, The thermoplastic resin comprises a polyolefin resin, The triglycerides include: (a) a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule, or (b) A triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

2. The nonwoven fabric according to claim 1, wherein The triglycerides do not contain groups derived from unsaturated fatty acids.

3. The nonwoven fabric according to claim 1 or 2, wherein The triglyceride contains at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

4. The nonwoven fabric according to claim 3, wherein The triglyceride contains at least a group derived from a saturated fatty acid having 16 carbon atoms and a group derived from a saturated fatty acid having 18 carbon atoms in one molecule.

5. The nonwoven fabric according to claim 1 or 2, wherein Based on the total amount of fatty acid-derived groups contained in all the triglycerides contained in the fiber, the proportion of groups derived from fatty acids with 16 carbon atoms is greater than 1 mass % and less than 55 mass %, and the proportion of groups derived from fatty acids with 18 carbon atoms is greater than 5 mass % and less than 90 mass %.

6. The nonwoven fabric according to claim 1 or 2, wherein Based on the total amount of groups derived from fatty acids contained in all the triglycerides contained in the fiber, the proportion of groups derived from fatty acids with 16 carbon atoms is greater than 10 mass% and less than 55 mass%, and the proportion of groups derived from fatty acids with 18 carbon atoms is greater than 45 mass% and less than 90 mass%.

7. The nonwoven fabric according to claim 1 or 2, wherein Based on the total amount of groups derived from fatty acids contained in all the triglycerides contained in the fiber, the proportion of groups derived from fatty acids with 16 carbon atoms is greater than 20 mass% and less than 50 mass%, and the proportion of groups derived from fatty acids with 18 carbon atoms is greater than 50 mass% and less than 70 mass%.

8. The nonwoven fabric according to claim 1 or 2, wherein Based on the total amount of groups derived from fatty acids contained in all the triglycerides contained in the fiber, the proportion of groups derived from fatty acids with 16 carbon atoms is greater than 25 mass% and less than 45 mass%, and the proportion of groups derived from fatty acids with 18 carbon atoms is greater than 55 mass% and less than 65 mass%.

9. The nonwoven fabric according to claim 1 or 2, wherein The triglyceride consists only of (a) or (b): (a) a mixture of a triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms in one molecule and a triglyceride containing at least a group derived from a fatty acid having 18 carbon atoms in one molecule, (b) A triglyceride containing at least a group derived from a fatty acid having 16 carbon atoms and a group derived from a fatty acid having 18 carbon atoms in one molecule.

10. The nonwoven fabric according to claim 1 or 2, wherein The mass ratio of the groups derived from fatty acids having 18 carbon atoms to the groups derived from fatty acids having 16 carbon atoms contained in all the triglycerides contained in the fiber is 1.0 or more and 15.0 or less.

11. The nonwoven fabric according to claim 1 or 2, wherein The mass ratio of the groups derived from fatty acids having 18 carbon atoms to the groups derived from fatty acids having 16 carbon atoms contained in all the triglycerides contained in the fiber is 1.3 or more and 5.0 or less.

12. The nonwoven fabric according to claim 1 or 2, wherein The relaxation time of pulsed NMR measured on the fiber is 10 μs or longer.

13. The nonwoven fabric according to claim 1 or 2, wherein The fiber diameter of the fibers is 0.1 μm or more and 40 μm or less.

14. The nonwoven fabric according to claim 1 or 2, having a weight per unit area of ​​0.2 g / m 2 Above and 50 g / m 2 the following. The nonwoven fabric according to claim 1 or 2, which is a meltblown nonwoven fabric or a composite nonwoven fabric having a meltblown layer.

16. The nonwoven fabric according to claim 1 or 2, wherein The nonwoven fabric comprises at least a spunbond layer and a meltblown layer. The mass ratio of the spunbond layer to the total mass of the nonwoven fabric is 50 mass % or more and 95 mass % or less, The mass ratio of the meltblown layer to the total mass of the nonwoven fabric is 5 mass % or more and 50 mass % or less.

17. The nonwoven fabric according to claim 1 or 2, wherein: The polyolefin resin is polypropylene.

18. The nonwoven fabric according to claim 1 or 2, wherein The triglyceride is contained in an amount of 1% by mass to 30% by mass based on the fiber containing the triglyceride.

19. The nonwoven fabric according to claim 18, wherein The triglyceride is contained in an amount of 9% by mass or more and 14% by mass or less based on the fiber containing the triglyceride.

20. The nonwoven fabric according to claim 1 or 2, wherein The ratio of the fibers containing the triglyceride in the nonwoven fabric is 3% by mass or more.

21. The nonwoven fabric according to claim 1 or 2, wherein The polyolefin resin includes a random propylene copolymer and homopolypropylene, or includes low stereoregular homopolypropylene and homopolypropylene, and the homopolypropylene is a homopolypropylene other than low stereoregular homopolypropylene.

22. The nonwoven fabric according to claim 21, wherein The ratio of the random propylene copolymer or the low-stereoregularity homopolypropylene to the fibers is 5% by mass or more and less than 60% by mass.

23. The nonwoven fabric according to claim 22, wherein The ratio of the random propylene copolymer or the low-stereoregularity homopolypropylene to the fibers is 9% by mass or more and less than 30% by mass.

24. The nonwoven fabric according to claim 1 or 2, comprising a meltblown layer and a spunbond layer. The meltblown layer comprises fibers, The fiber contains a random propylene copolymer, homopolypropylene and the triglyceride, or contains low stereoregular homopolypropylene, homopolypropylene and the triglyceride, wherein the homopolypropylene is a homopolypropylene other than low stereoregular homopolypropylene.

25. The nonwoven fabric according to claim 1, wherein The polyolefin resin comprises a random propylene copolymer and homopolypropylene, or comprises low stereoregular homopolypropylene and homopolypropylene, wherein the homopolypropylene is a homopolypropylene other than the low stereoregular homopolypropylene. Based on the total amount of groups derived from fatty acids contained in all the triglycerides contained in the fiber, the proportion of groups derived from fatty acids with 16 carbon atoms is greater than 20 mass% and less than 50 mass%, and the proportion of groups derived from fatty acids with 18 carbon atoms is greater than 50 mass% and less than 70 mass%.

26. The nonwoven fabric according to claim 1, wherein The polyolefin resin comprises a random propylene copolymer and homopolypropylene, or comprises low stereoregular homopolypropylene and homopolypropylene, wherein the homopolypropylene is a homopolypropylene other than the low stereoregular homopolypropylene. The triglyceride is extremely hardened palm oil.

27. The nonwoven fabric according to claim 26, wherein The ratio of the random propylene copolymer or the low stereoregular homopolypropylene to the fiber is 5% by mass or more and less than 60% by mass, The triglyceride is contained in an amount of 1% by mass to 30% by mass based on the fiber containing the triglyceride.

28. The nonwoven fabric according to claim 27, wherein The triglyceride is contained in an amount of 9% by mass or more and 14% by mass or less based on the fiber containing the triglyceride.

29. The nonwoven fabric according to claim 26 or 27, wherein The ratio of the random propylene copolymer or the low-stereoregularity homopolypropylene to the fibers is 9% by mass or more and less than 30% by mass.

30. The nonwoven fabric according to claim 26 or 27, comprising a meltblown layer and a spunbond layer. The meltblown layer comprises fibers, The fiber contains the random propylene copolymer, the homopolypropylene and the triglyceride, or contains the low stereoregular homopolypropylene, the homopolypropylene and the triglyceride.

31. The nonwoven fabric according to claim 1 or 2, wherein The polyolefin resin includes a random propylene copolymer and homopolypropylene, and the homopolypropylene is a homopolypropylene excluding low stereoregular homopolypropylene.

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