JPH10204768A - Filament nonwoven fabric and absorbing article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a filament nonwoven fabric comprising specific thermally fusible conjugate fibers containing inorganic substance powder in a prescribed amount, good in adhesivity to different kinds of materials, excellent in touch, flexibility, uniformity and operability, and useful for absorbing articles, etc. SOLUTION: This filament nonwoven fabric comprises thermally fusible conjugate filaments formed from the first component forming at least a part of the surfaces of the filaments in the longitudinal direction of the filaments and from the second component comprising a crystalline thermoplastic resin such as polypropylene and having a higher melting point than that of the first component, and further contains inorganic substance powder (preferably having an average particle diameter of 0.04-2μm) such as titanium dioxide powder in a concentration of 500-50000wt.ppm in the filaments. The first component comprises e.g. the mixture of polyethylene with >=20wt.% of an ethylene-acrylate ester-maleic anhydride copolymer having a maleic anhydride fraction of 2-5wt.%, an acrylate ester fraction of 6-30wt.% and a melting point of 60-110 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a long-fiber nonwoven fabric and an absorbent article using the same. In particular, the present invention relates to a first component containing at least 20% by weight of an ethylene-acrylate-maleic anhydride copolymer and forming at least a part of the fiber surface in the length direction of the fiber; The present invention relates to a heat-fusible composite long-fiber nonwoven fabric using a crystalline thermoplastic resin having a higher melting point than the component as a second component, and an absorbent article using the same.

[0002]

2. Description of the Related Art Spunbonded nonwoven fabrics, which are typical examples of long-fiber nonwoven fabrics, introduce a group of long fibers discharged from a melt spinneret into an air soccer or the like, draw and stretch them, open them and collect them on a collection conveyor. After obtaining a fibrous web, the filaments are produced by entanglement or heat fusion between the long fibers by an appropriate means. Therefore, since long fibers, which can be called continuous fibers, are used as constituent fibers, mechanical properties such as tensile strength are superior to short fiber nonwoven fabrics using short fibers as constituent fibers. In addition, since long fibers obtained by melt spinning can be opened and accumulated as they are to obtain a nonwoven fabric, it is more reasonable than a nonwoven fabric obtained by opening and accumulating short fibers by a dry method or a wet method. It has the advantage that it can be produced in recent years, and in recent years its production has been greatly increased.

[0003] Further, as heat-fusible conjugate fibers, conventionally, polypropylene and polyester having a high melting point component and high-density polyethylene, low-density polyethylene, linear low-density polyethylene and the like having a low melting point component are known. ing. Such conventional heat-fusible conjugate fibers are usually formed into a web, and then heated or heated to the melting point of the low-melting component so that the contact portions between the fibers are softened or melted and joined. Form. However, these heat-fusible conjugate fibers have a low melting point component,
Poor bonding or adhesion with other foreign materials such as paper, rayon, glass. Therefore, when the above-mentioned nonwoven fabric is used by being bonded or adhered to another foreign material, or when it is used in combination with another material to form a composite material, it is necessary to use a new binder. However, the adhesiveness was not always good.

Conventionally, absorbent articles such as disposable diapers and sanitary napkins, such as disposable diapers of medical hygiene materials,
Although different depending on the mode, an absorbent core layer for absorbing and retaining bodily fluids such as urine and blood, and a liquid-permeable absorbent core for enclosing the absorbent core layer, for absorbing bodily fluids such as urine and blood and preventing leakage. The cover of the layer, the liquid-permeable topsheet disposed on the surface side (side in contact with the skin), and the absorbed body fluid disposed on the back surface of the absorbent core layer (the side opposite to the side where the topsheet is located) A liquid-impervious back sheet or the like to prevent the liquid from leaking to the outside, and further, a position between the cover of the absorbent core layer and the top sheet or the cover of the absorbent core layer and the absorbent core layer. It is inserted at a position between the two to provide cushioning, diffuse body fluid, or prevent any body fluid absorbed by the absorbent core layer from returning to the skin side. To secure It would also be present in the structure having Ndoshito. The function of preventing the bodily fluid absorbed in the absorbent core layer from returning to the skin side is, for example, to reduce the filling density of the fibers of the second sheet to be smaller than the filling density of the fibers of the absorbing core layer, and to increase the fiber filling density. This is based on the principle of absorbing body fluids by capillary action or the like, but is not particularly limited to this method. In addition to this, further sheets are inserted to provide various functions,
Some are more multilayered.

As the absorbent core layer, for example, a combination of an aggregate of cellulosic fibers such as fluff pulp and a highly water-absorbent resin is generally used. Hardened ones are used. As a cover of the liquid-permeable absorbent core layer for wrapping the absorbent core layer, tissue paper is usually used. As the top sheet, a through-air nonwoven fabric made of short fibers (a nonwoven fabric in which a part of the short fibers constituting the nonwoven fabric is bonded by hot air heating) or an embossed nonwoven fabric made of short fibers (a hot embossed roll and a smooth surface) Is passed between the rolls having a non-woven fabric in which some of the short fibers constituting the non-woven fabric are bonded to each other), and as a back sheet, a thermoplastic film is used, The thermoplastic film has countless micropores to prevent internal stuffiness during wearing,
It is common to have air permeability. In addition, a film composited with a nonwoven fabric has been used from the viewpoint of improving the feel and appearance of the plastic characteristic of the film and improving the strength. Necessary portions are appropriately bonded to each other with a hot melt adhesive or the like.

However, hot-melt adhesives are tacky and do not have a very strong adhesive force as in the case of bonding with an adhesive, and if used in an excessively large amount, these sheets may become clogged. As a result, there is a problem that air permeability is impaired or body fluid permeability is reduced.

[0007]

As for the long-fiber nonwoven fabric, in order to solve the above-mentioned problems, as a component used as a heat-sealing component of a heat-fusible composite long-fiber nonwoven fabric, it has various functional groups, Considered the use of ethylene-acrylate-maleic anhydride copolymer, which is a resin with high adhesiveness, as one component of composite filaments. However, it was found that there was a problem that it had very strong tackiness and a large coefficient of friction.

For this reason, when the yarn discharged from the spinning nozzle hole is pulled by a metal air soccer, fineness unevenness occurs due to friction between the fiber and the metal or between the fibers, or the fibers are fused with each other. There is a problem that it is difficult to spread the fiber when it is worn.

The ethylene-acrylic acid ester-maleic anhydride copolymer has a low crystallinity, a low melting point or a low softening point due to various functional groups introduced into the ethylene copolymer. ing. When a resin having low crystallinity is used as described above, the time or distance (solidification length) until the resin thread discharged in a molten state from the spinning nozzle hole crystallizes and solidifies becomes extremely long. ing.

[0010] Therefore, not only the filaments become bundles due to friction, causing unevenness of fineness or poor opening, but also the filaments having a longer solidified length are still melted by the fact that the distance between the filaments becomes shorter. Since the ethylene-acrylic acid ester-maleic anhydride copolymer having a low melting point or a low softening point contacts in a molten state, so-called thread breakage occurs, resulting in a problem of poor operability.

Japanese Patent Application Laid-Open No. 3-287875 discloses that an ethylene-acrylate-maleic anhydride copolymer is used as a low melting point component, a silicone emulsion polymer is substantially adhered to the surface, and the friction coefficient of the fiber surface is reduced. A heat-fusible conjugate fiber in which the heat resistance is reduced is disclosed. Therefore, it is considered that a nonwoven fabric excellent in homogeneity can be easily obtained by using this technique even with a fiber using an ethylene-acrylate-maleic anhydride copolymer as a low melting point component.

However, the method disclosed in Japanese Patent Application Laid-Open No.
The technique described in No. 5 assumes only short fibers. In this case, a finish such as a silicone emulsion polymer is mixed with various surfactants and adheres to the fiber surface in the form of an aqueous emulsion. It is common. The problem during the production of long-fiber nonwoven fabrics is that when they are pulled by metal air soccer, they need to adhere between the spinneret and air soccer. Problems such as difficulty in adhering the liquid itself, splashing of the adhering liquid in air soccer, fiber convergence due to the surface tension of the water-based emulsion, and applying the same charge by corona discharge to open the fiber by charging. Also in such a case, there is a problem that the spreadability is substantially poor due to a decrease in chargeability and the like, which is not suitable for directly manufacturing a long-fiber nonwoven fabric.

That is, even when the technique described in JP-A-3-287875 is used, the spreadability is insufficient, the formation (uniformity of the nonwoven fabric) is poor, and the flexibility of the long-fiber nonwoven fabric is low. The texture, such as texture and feel, is not yet sufficient, and this technique has not been suitable for manufacturing long-fiber nonwoven fabrics.

The present invention has been made to solve the above-mentioned problems, and has high adhesiveness, low-temperature adhesiveness, and good adhesiveness with different kinds of materials. It is an object of the present invention to provide a long-fiber nonwoven fabric made of a conjugate fiber having excellent texture, uniformity of the nonwoven fabric, and good operability such as spinnability.

Further, the present invention solves the above-mentioned problems of the conventional absorbent articles, and uses the long-fiber nonwoven fabric for at least a part of the absorbent articles to improve the adhesiveness without causing clogging or the like. It is an object of the present invention to provide an absorbent article which is excellent and free from the problems caused by peeling and collapse of a layer constituting the absorbent article during use.

As a result of intensive studies, the present inventors have found that by adding an inorganic powder to at least the first component which is a low melting point or low softening point component, the inorganic powder is exposed to the fiber surface and Fine irregularities can be imparted, and the contact area between the fibers can be reduced, preventing the fibers from sticking to each other during spinning, reducing yarn breakage, improving operability, and adding inorganic powder. Also, almost no increase in the crystallization temperature of the ethylene-acrylate-maleic anhydride copolymer occurs, and the increase in the crystallinity is remarkably small.
A long-fiber nonwoven fabric having good flexibility and softness and excellent adhesiveness with different materials can be obtained without impairing the characteristics of the maleic anhydride copolymer, such as flexibility and high adhesion, low-temperature adhesion, and By using such a long-fiber nonwoven fabric for at least a part of an absorbent article, it is possible to improve the adhesiveness without causing clogging or the like and to cause a problem caused by peeling or collapse of a layer constituting the absorbent article during use. It was found that an absorbent article free from the above was obtained, and the present invention was completed.

[0017]

In order to solve the above-mentioned problems, a long-fiber nonwoven fabric according to the present invention contains at least 20% by weight of an ethylene-acrylate-maleic anhydride copolymer and has at least a fiber surface. A first component partially formed in the length direction of the fiber, and a heat-fusible conjugate long fiber having a crystalline thermoplastic resin having a higher melting point than the first component as a second component, at least the first component The composition contains an inorganic powder, and the content of the inorganic powder is 500 to 50 in terms of fiber concentration.
000 ppm by weight.

In the long-fiber nonwoven fabric of the present invention, the copolymer composition of the ethylene-acrylate-maleic anhydride copolymer has a maleic anhydride content of 2 to 5% by weight and an acrylic acid ester content of It is preferably from 6 to 30% by weight.

Further, in the long-fiber nonwoven fabric of the present invention, the ethylene-acrylic acid ester-maleic anhydride copolymer preferably has a melting point of 60 to 110 ° C. Also,
In the long-fiber nonwoven fabric of the present invention, the resin component as the first component is preferably a mixture of an ethylene-acrylate-maleic anhydride copolymer and polyethylene.

In the long-fiber nonwoven fabric of the present invention, the inorganic powder preferably has an average particle diameter of 0.04 to 2 μm. Further, in the long-fiber nonwoven fabric of the present invention, the inorganic powder is preferably at least one inorganic powder selected from titanium dioxide, silica, alum, calcium carbonate, calcium oxide, magnesium oxide, and talc.

In the long-fiber nonwoven fabric of the present invention, the crystalline thermoplastic resin as the second component is preferably polypropylene. Further, in the long-fiber nonwoven fabric of the present invention,
Preferably, the crystalline thermoplastic resin of the second component is polyethylene terephthalate.

In the long-fiber nonwoven fabric of the present invention, the long-fiber nonwoven fabric is preferably a long-fiber nonwoven fabric obtained by a spunbonding method. Further, the absorbent article of the present invention is an absorbent article using the long-fiber nonwoven fabric according to any of the above for at least a part thereof.

[0023]

DETAILED DESCRIPTION OF THE INVENTION The nonwoven fabric of the present invention contains at least 20% by weight of an ethylene-acrylate-maleic anhydride copolymer and has at least a part of the fiber surface formed in the length direction of the fiber. The first component, comprising a heat-fusible conjugate long fiber having a crystalline thermoplastic resin having a higher melting point than the first component as a second component, containing at least a first component containing an inorganic powder, Content is 5 in fiber concentration
It is a long-fiber nonwoven fabric containing 0.00 to 50,000 weight ppm.

The first component is a resin containing at least 20% by weight of the ethylene-acrylate-maleic anhydride copolymer and forming at least a part of the fiber surface in the fiber length direction. As the heat-adhesive conjugate fiber having a crystalline thermoplastic resin having a higher melting point than one component as a second component, a sheath-core composite fiber in which the first component is a sheath component and the second component is a core component, In this case, a so-called sheath-core eccentric type composite fiber in which the position in the cross section of the core component is eccentric, and a so-called side-by-side type composite fiber (side-by-side type composite fiber) in which the first component and the second component are bonded are preferably used. In particular, it is preferable to use a sheath-core eccentric conjugate fiber or a side-by-side conjugate fiber, since a crimped fiber can be easily obtained and a bulky and comfortable long-fiber nonwoven fabric can be obtained. Ratio of first component and second component in cross section of side-by-side composite fiber (composite ratio)
May be 1: 1 and one component may of course occupy a larger cross-sectional area in the fiber cross-section than the other component.

The volume ratio of the first component and the second component of the conjugate fiber (when a fiber cross section is employed, it corresponds to the area ratio of the cross section = composite ratio) is usually the ratio of the first component to the second component. 10:90 to 90:10, preferably 30:70 to 7
0:30 is used.

In the present invention, as the resin component used as the first component, a resin containing 20% by weight or more of an ethylene-acrylate-maleic anhydride copolymer is used.

The ethylene-acrylic ester-maleic anhydride copolymer has a maleic anhydride fraction (ie, the copolymerization ratio of the maleic anhydride component) of about 2 to 5% by weight, and an acrylate ester fraction (ie, acrylic An ethylene-acrylate-maleic anhydride copolymer having an acid ester component copolymerization ratio of about 6 to 30% by weight is preferably used. Usually, an ethylene-acrylate-maleic anhydride terpolymer is used, but some other components may be copolymerized without alienating the object of the present invention. An ethylene-acrylate-maleic anhydride copolymer having a maleic anhydride content of 2 to 5% by weight and an acrylic acid ester content of 6 to 30% by weight has too low a melting point and too large a tackiness. Without having, it satisfies the necessary properties as a material constituting the fiber surface, and has a relatively good thermal stability, so that there are few problems of thermal decomposition and alteration in melt spinning, and it is suitable. It is preferable because it has excellent thermal adhesion to foreign materials.

In the present invention, the ethylene-acrylate-maleic anhydride copolymer has a melting point of 60%.
An ethylene-acrylate-maleic anhydride copolymer at a temperature of from -110 ° C is preferably used because of good spinnability and adhesion.

The acrylate component constituting the ethylene-acrylate-maleic anhydride copolymer used in the present invention is not particularly limited, but industrially, generally ethyl acrylate and butyl acrylate are generally used. Since copolymers using such are widely used, they are easily available and preferred, and because of the free alcohol derived from the acrylate component, they pose a problem in terms of odor and food hygiene. In the field, ethyl acrylate which does not have a strong odor and is registered in the "Self-regulatory Standards for Food Packaging Made of Synthetic Resins such as Polyolefin" of the Hygiene Council for Polyolefins is preferably used.

In the resin component constituting the first component, the ethylene-acrylic ester-maleic anhydride copolymer contains at least 20% by weight based on the total weight of the resin component in the first component. Is necessary to maintain good low-temperature adhesion and adhesion to other foreign materials.
When the amount is less than the weight percentage, the above characteristics cannot be sufficiently exhibited, which is not preferable. The ethylene-acrylate-maleic anhydride copolymer can be used up to 100% by weight based on the total weight of the resin components in the first component, but if necessary, can be melt-spun. A resin having a relatively low melting point or a low softening point can be used in the range.

The resin having a relatively low melting point or low softening point used in the first component by mixing with the ethylene-acrylate-maleic anhydride copolymer includes, for example, polyethylene, polypropylene, ethylene-propylene copolymer , Ethylene-butene-propylene copolymer, low-melting polyester, low-melting polyamide and the like.
Among these resins having a relatively low melting point or low softening point, polyethylene is preferable from the viewpoint of ensuring compatibility and a low melting point temperature, and various polyethylenes can be used. For example, high density polyethylene, low density polyethylene,
Linear low-density polyethylene and the like can be suitably used. The combined use of polyethylene and the like is preferable because friction with a metal such as air soccer described above during melt spinning can be further reduced and adhesion between fibers can be more suitably prevented.

As the resin component of the first component containing 20% by weight or more of the ethylene-acrylate-maleic anhydride copolymer used in the present invention, the first component is heat-melted at a lower temperature than the crystalline thermoplastic resin of the second component. Alternatively, any material capable of softening and exhibiting heat-sealing properties may be used. In the case where the obtained long-fiber fleece is heat-sealed, it is preferable that the second component does not damage the second component, such as deterioration of physical properties due to heat.

The crystalline thermoplastic resin of the second component used in the present invention has a melting point higher than the melting point of the resin component containing the ethylene-acrylate-maleic anhydride copolymer of the first component, A crystalline thermoplastic resin capable of composite spinning with the first component is used, preferably,
Examples include polypropylene or polyethylene terephthalate. The use of polypropylene as the second component is preferable because a relatively flexible long-fiber nonwoven fabric can be obtained. Further, when polyethylene terephthalate is used as the second component, a long-fiber nonwoven fabric having higher strength and more excellent elasticity (cushioning property) when crimping is developed can be obtained, which is preferable. .

The MFR (melt flow rate) of the resin used is not particularly limited, but the first component and the second component (provided that the second component is an olefin resin) are generally 10 to 10. 100 g / 10 min is used. When the resin of the second component is an olefin-based polymer, any of those polymerized using a Ziegler / Natta-based catalyst and those polymerized using a so-called metallocene-based catalyst can be used.

As the inorganic powder used in the present invention, any inorganic powder may be used as long as it can impart irregularities to the fiber surface and prevent sticking between the fibers. The average particle diameter of the inorganic powder is preferably 0.04 to 2 μm, and particularly preferably 0.04 to 1 μm. Even if the particle size is too small, the cost will increase,
It is easy to cause secondary agglomeration, clogging of filters and spinning nozzles, and it is easy to cause breakage of yarns and decrease operability.If the particle size is too large, inorganic powder The above range is particularly preferable because the dispersibility tends to be poor, the filter and the spinning nozzle are likely to be clogged, and yarn breakage tends to be caused to lower the operability. The particle size of the inorganic powder can be measured by observation with an electron microscope. For example, when measuring the particle diameter of the inorganic powder contained in the composite long fiber, by heating the composite long fiber under vacuum, the polymer and the inorganic powder constituting the composite long fiber After separation, it can be measured by electron microscope observation. At this time, if the particles have a shape other than a spherical shape, the particle size is converted into a particle size assuming that the sphere has the same volume as the particle.

Specific examples of the inorganic powder used in the present invention include various stable inert powders such as titanium dioxide, silica, alum, calcium carbonate, calcium oxide, magnesium oxide, and talc. These inorganic powders can impart fine irregularities to the surface of the conjugate fiber, and as a result, prevent adhesion between the fibers during spinning, and as described above in a composite long-fiber nonwoven fabric such as a spunbond nonwoven fabric. Good fineness unevenness and openability, improved yarn breakage, and good operability.In addition, these inorganic powders have a relatively small nucleating effect, and thus have a low melting point or high adhesion ethylene as the first component. -A resin component containing an acrylate-maleic anhydride copolymer does not impair the flexibility, high adhesion, low-temperature adhesion, and other characteristics of the resin component. Thus, a long-fiber nonwoven fabric having excellent adhesiveness can be obtained. In particular, titanium dioxide, silica, alum, calcium carbonate, calcium oxide, magnesium oxide, and talc are preferable because they have a smaller nucleating effect. These inorganic powders may be pure, but the cost is industrially high.Therefore, as long as the object of the present invention is not impaired, the use of a powder containing impurities is not a problem. . Titanium dioxide includes rutile-type titanium dioxide and anatase-type titanium dioxide, all of which can be used, but rutile-type titanium dioxide is preferable in terms of good weather resistance and heat resistance. Further, the inorganic powder needs to be added to at least the first component, and may be added to both the first component and the second component.

The inorganic powder may be introduced from a side feeder provided in an extruder, kneaded and added together with melt extrusion. Further, for example, it may be added in the form of a compound or a master batch kneaded with the first component in advance. When kneading the inorganic powder, an appropriate dispersant is usually used to improve the dispersibility.

The amount of the inorganic powder added is 5
It must be contained in the range of 00 to 50,000 ppm by weight. If the amount of the inorganic powder is too small, the effect of preventing the fibers from sticking to each other during spinning due to the provision of fine irregularities on the fiber surface is not sufficiently exhibited, and the long fibers become bundles due to friction, resulting in unevenness and opening of the fineness. This is not preferable because of the occurrence of defects and breakage of yarn, resulting in a decrease in operability. On the other hand, if the amount of the inorganic powder is too large, clogging of the filter or the spinning nozzle may occur, or thread breakage may occur, resulting in poor operability, which is not preferable. In addition, when the long-fiber nonwoven fabric of the present invention is used particularly for a sanitary napkin, the amount of the inorganic powder to be added is preferably 12,000 ppm by weight or less in terms of the total amount of resin ash.

In the case of a conjugate fiber, the concentration in the fiber in the amount of the inorganic powder added is the concentration in the entire fiber. Therefore, even if the inorganic powder is added only to the first component,
The concentration indicates an average concentration of the entire composite fiber composed of the first component and the second component.

In the present invention, the fineness of the composite long fiber constituting the nonwoven fabric is not particularly limited, and may be an appropriate fineness according to the type and use of the material resin used. It is preferably about 1 to 8 d / f. For example, when used for sanitary materials represented by disposable diapers, sanitary napkins, incontinence pads, surgical clothing, surgical hangers, haptics, etc.
d / f is preferred.

The basis weight of the long-fiber nonwoven fabric of the present invention is not particularly limited, and may be a nonwoven fabric having a basis weight appropriate for the type and use of the material resin used, and preferably 10 to 50 g / m ^2.
About 10 to 30 especially when used for sanitary materials.
g / m ² is preferred.

Using the resin composition of the first component and the second component as described above, melt spinning is performed to obtain a composite long fiber from a die, and the long fiber nonwoven fabric according to the present invention can be obtained. The long-fiber nonwoven fabric can be easily manufactured by a well-known spunbond method.

The spunbond method is already well known and will not be described in detail. For example, a low-melting resin component containing at least 20% by weight of an ethylene-acrylate-maleic anhydride copolymer and an inorganic material A powder mixture is prepared as a first component, and a crystalline thermoplastic resin having a higher melting point than the first component (a crystalline thermoplastic resin mixed with an inorganic powder may be used if necessary) is used as a second component. Prepare as. Each of these resin compositions is put into an individual extruder, and is melt-spun using a composite spinneret. The fiber group discharged from the spinneret is introduced into an air soccer and drawn and stretched to obtain a long fiber group. Subsequently, the long fiber group discharged from the air soccer is fed to an appropriate charging device such as a corona discharge device. After applying a charge and charging, the fiber is opened by passing between a pair of vibrating wings (flaps), or the fiber is opened by colliding with an appropriate reflecting plate or the like,
The opened long fiber group is collected as a long fiber fleece on an endless net-shaped conveyor provided with a suction device on the back surface. The collected long fiber fleece is conveyed while being placed on an endless conveyor, and introduced between pressurized rolls of a point bond processing machine composed of a heated uneven roll and a smooth roll to remove the long fiber fleece. The first component is melted or softened in a region corresponding to the convex portion of the concave-convex roll to obtain a long-fiber nonwoven fabric in which long fibers are heat-sealed to each other. The basis weight of the long-fiber nonwoven fabric can be adjusted, for example, by adjusting the spinning discharge speed (discharge amount per time), the moving speed of the endless conveyor, and the like. The formation of the nonwoven fabric of the long fiber fleece (entanglement or heat fusion) is not limited to the point bond method, and may be performed by a hot air heating method, a high pressure water flow method, a needle punch method, an ultrasonic heating method, or the like. A plurality of combinations of these nonwoven fabric methods may be employed.

The long-fiber nonwoven fabric of the present invention is not limited to the one manufactured by the method described above, but the spunbond method can easily produce a nonwoven fabric having excellent mechanical properties such as tensile strength. The obtained and spun filaments obtained by melt-spinning can be unfolded and accumulated as they are to obtain a non-woven fabric.

The thus obtained long-fiber nonwoven fabric of the present invention has high adhesion, low-temperature adhesion, and good adhesion to different kinds of materials. A long-fiber nonwoven fabric made of a conjugate fiber with excellent uniformity and good operability such as spinnability can be obtained, so it can be used for various applications, especially when used by bonding or bonding with other materials, or When combined with other materials to form a composite material, it can be easily thermally bonded,
It can be used effectively for the production of such composite materials.

Further, the long-fiber nonwoven fabric of the present invention can also be used for at least a part of water-absorbent articles such as sanitary napkins and disposable diapers. Disposable diapers, absorbent articles such as sanitary napkins also vary depending on the mode,
As described above, in order to absorb body fluids such as urine and blood and prevent leakage, a cover of an absorbent core layer that absorbs and retains body fluids such as urine and blood, and a liquid-permeable absorbent core layer that wraps the absorbent core layer And a liquid-permeable top sheet disposed on the surface side (side in contact with the skin), and disposed on the back side surface of the absorbent core layer (the side opposite to the side where the top sheet is located), so that the absorbed bodily fluids are It is composed of a liquid-impermeable back sheet or the like for preventing leakage, and further, a position between the cover of the absorbent core layer and the top sheet or a position between the absorbent core layer and the cover of the absorbent core layer. It is inserted at the position and provides any function such as imparting cushioning property, diffusing body fluid, or preventing body fluid absorbed by the absorbent core layer from returning to the skin side With a second seat There is also a thing of the configuration that. In addition to the above, there is a case in which another sheet is further inserted to provide various functions, and the sheet has a multilayer structure. Since the long-fiber nonwoven fabric of the present invention has excellent adhesiveness to other materials, it is used, for example, in a cover or a second sheet of the absorbent core layer or in the absorbent core layer, and is subjected to hot pressing or thermocompression bonding to reduce the thickness of the absorbent article. It is preferably used because it prevents floating of the top sheet and prevents the top sheet from clinging to a local area. When used in the absorbent core layer, for example, by inserting in the middle of the absorbent core layer and thermally bonding, without significantly impairing the absorption characteristics of the absorbent core layer, in a state where weight is worn while wearing Can be performed to prevent the absorbent core layer from collapsing due to stress caused by body movement. The hot press or thermocompression bonding preferably depends on the part to be used, but it is usually preferable to employ partial point bonding so that a large number of points can be bonded.

[0047]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to only those listed in these Examples.

Examples 1 to 8 and Comparative Examples 1 to 4 Ethylene acrylate-maleic anhydride terpolymer shown in Table 1 or a mixture thereof with other resin (first component in Table 1) When the use ratio (wt%) of the ethylene-acrylate-maleic anhydride terpolymer in the column (A) is other than 100%, the remainder other than the use ratio of the terpolymer is other than that. This is the ratio of resin used.)
A mixture with the inorganic powder shown in Table 1 was prepared as a first component. In addition, the addition ratio of the inorganic powder shown in Table 1 is represented by the fiber concentration as defined above. Therefore, the concentration of the inorganic powder only in the first component is higher than the concentration shown in the table (the concentration of the inorganic powder only in the first component can be easily calculated from the fiber concentration and the composite ratio). As the second component, a crystalline thermoplastic resin having the properties shown in Table 1 was prepared. Comparative Example 4 is a single fiber of only the second component, that is, polypropylene. These resin compositions,
Each of the extruders was put into a separate 60 mmφ extruder, and the extrusion temperature of the first component was the temperature shown in Table 1, and the extrusion temperature of the second component was 250 ° C. for polypropylene (250 ° C. for Comparative Example 4). When the second component is polyethylene terephthalate, the extrusion temperature is 280 ° C., and the first component,
The total amount of the two components is 2200 according to the composite ratio of the second component.
cc / min (specifically, the composite ratio A / B of the first component (A) and the second component (B) is 50/5
In the case of 0, the extrusion ratio of the first component is 1100 cc /
Min. And the extrusion rate of the second component are 1100 cc / min.), Respectively, using a parallel type, a sheath-core type or a sheath-core eccentric type spinneret as described in the composite mode column of the table. It was melt spun. The spinneret used had a circular spinning hole with a hole diameter of 0.35 mm in 550 pieces × 5 rows in the longitudinal direction of the spinneret. The fiber group discharged from the spinneret was introduced into an air soccer and drawn and stretched to obtain a long fiber group. Subsequently, the group of long fibers discharged from the air soccer was charged with the same charge by a corona discharge device, charged, and then passed between a pair of vibrating blades to open. The opened filament group was collected as a filament fleece on an endless conveyor provided with a suction device on the back surface. At this time, the drawing / drawing speed of the air soccer was appropriately adjusted depending on the type of the fiber so that the fineness of the long fiber was 2.2 d / f. The concentration of the inorganic powder in the fiber was as shown in the table. The collected long fiber fleece was conveyed while being placed on an endless conveyor, and introduced between pressurized rolls of a point bond processing machine composed of a heated uneven roll and a smooth roll. The introduced long-fiber fleece obtained a long-fiber nonwoven fabric in which the first component was melted or softened in the area corresponding to the convex portion of the concavo-convex roll, and the long fibers were heat-sealed to each other. The moving speed of the endless conveyor is set to 50 depending on the type of the fiber so that the basis weight of the long-fiber nonwoven fabric is 30 g / m ^2.
m / min. Was adjusted before and after the reference. In addition,
The peripheral speed of the uneven roll was the same as the moving speed of the endless conveyor. The linear pressure and the roll temperature between the rolls were set according to the rigidity and softness of the long-fiber nonwoven fabric (the 45 ° cantilever method of the A method of JISL 1096, but the sample size was 5 cm × 15
cm. ) Has an average value of 35 mm in the vertical and horizontal directions
It was set appropriately so as to be near.

In the examples, all the nonwoven fabrics (thermal fusion between long fibers) were performed by the point bond method in order to adjust the conditions at the time of the sensory test such as hand feeling. A water flow method, a needle punch method, an ultrasonic heating method, or the like may be used, or a combination of a plurality of these nonwoven fabric methods may be used.

When polypropylene is used as the second component, MFR (melt flow rate: JIS K)
7210 was used under conditions 14 in Table 1) of 35. When polyethylene terephthalate was used as the second component, the one having an IV (intrinsic viscosity) value of 0.63 and a melting point of 255 ° C. was used. The IV value was measured at 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent. The MI (melt index) of various polyethylenes used for the first component is JIS.
K7210 Measured under condition 4 of Table 1.

The average particle diameter of the inorganic substances shown in Table 1 was 0.04 μm for silica, 0.20 μm for TiO ₂ ,
Alum is 0.95 μm, CaCO ₃ is 0.08 μm
m, CaO of 0.35 μm, MgO of 0.17 μm and talc of 0.40 μm were used. Incidentally, rutile type titanium dioxide was used as TiO ₂ . In the table, PP of the second component means polypropylene, and PET means polyethylene terephthalate. Also, the volume ratio A / B in the column of the composite ratio
A indicates the numerical value of the first component, B indicates the numerical value of the second component,
It is set to 100 for the entire composite fiber.

Table 2 shows the evaluation results of the long-fiber nonwoven fabric obtained as described above. The measuring methods and evaluation criteria for each evaluation item are as follows. (Adhesive Strength with Other Materials <Peel Strength>) The samples (long-fiber nonwoven fabrics) obtained in the examples and comparative examples and the samples to be bonded were each cut into a size of 10 cm × 5 cm. The samples are overlapped so that the four corners thereof are aligned, and a thin and long heat seal is applied in the short side direction, that is, the width direction of the overlapped samples. The position where the heat sealing is performed is a portion extending from 1 cm in the longitudinal direction to 2 cm inside from one end of the short side of the overlapped sample. That is, a 1-cm-wide blank portion without heat sealing was provided in parallel with the short side from one end of the short side of the sample, and a 1-cm-wide heat seal was performed adjacent to the blank portion and parallel to the short side. The heat sealing condition is temperature 1
50 ° C. (both upper and lower), 3 kg / cm ² , 5 seconds. As a heat sealing device, “Heat Seal Tester TP-
701 "(manufactured by Tester Sangyo Co., Ltd.).

The sample for the tensile test obtained by the above operation was opened from the short side of the other end on which the heat sealing was not performed, and the ends thereof were set at 10 cm intervals with a Tensilon tensile tester (“RDM”). -100 "(made by Orientec Co., Ltd.) so as not to be twisted. The peel strength was measured at a pulling speed of 100.
mm / min, and the peel strength is calculated according to JIS L
1086-1983.

(Rigidity) The rigidity was measured in the vertical and horizontal directions according to the 45 ° cantilever method of Method A of JIS L 1096, and the average value was expressed. The sample size is 5c
m × 15 cm. In addition, as described above, the rigidity was determined by a point bond method in which the long fibers were heat-sealed with each other for the purpose of adjusting the conditions at the time of the sensory test such as hand feeling.
m. Therefore, it is not described in Table 2.

(Uniformity index of long fiber nonwoven fabric) 5 × 5 cm
Were sampled at equal intervals at five points in the lateral direction of the nonwoven fabric, and each was cut into 1 cm squares and weighed. From this, 5
For each point sample ((maximum value)-(minimum value))
× 100 / (average value) was calculated, and the average value was calculated. It was used as a measure of spread variability and fineness variability. It can be considered that the smaller the value is, the higher the uniformity is.

(Hand) Ten monitors performed a sensory test by touching the surface of the long-fiber non-woven fabric, and when they felt soft and comfortable, they were scored 1 point per person.
(Spinnability) Melt spinning was performed for 3 hours, and the number of occurrences of yarn breakage was measured. When the number of yarn breaks is 3 or less, the spinnability can be considered to be good.

(Measurement Method of Melting Point) The melting point can be measured using a DTA (differential thermal analysis) apparatus or a DSC (differential scanning calorimetry) apparatus. In the present invention, a DSC apparatus was used. In the present invention, what is measured by the following method is defined as the melting point.

Approximately 0.4 mg of sample is taken and weighed to the nearest 0.01 mg. As the sample container, an aluminum container having a uniform thickness and a purity of 99.9 to 99.99% is used. The sample is placed thinly in the center of the container, and is brought into close contact with the bottom surface of the sample container under constant pressure so that air does not enter the sample. The atmosphere gas uses nitrogen gas to remove oxygen and moisture. The heating rate was 10 ° C. per minute, and the measurement was carried out without subjecting the sample to a specific treatment such as once melting the sample in advance. The melting point is determined according to JIS K 7121-1987.
Compliant.

[0059]

[Table 1]

[0060]

[Table 2]

The abbreviations used in Tables 1 and 2 indicate the following. Abbreviations in Table 1

PP: isotactic polypropylene (MFR 35) PET: polyethylene terephthalate (IV 0.
HDPE: high-density polyethylene (MI 26) LLDPE: linear low-density polyethylene (MI 30) LDPE: low-density polyethylene (MI 35) Abbreviations in Table 2 Copolymer: ethylene-ethyl acrylate- Maleic anhydride terpolymer (E-EA-MAH) where E: ethylene, EA: ethyl acrylate, MA
H: maleic anhydride EH1: EA content 9.5% by weight, MAH content 2.5% by weight, melting point 102 ° C EH2: EA content 21.9% by weight, MAH content 3.0% by weight, melting point 80 ° C EH3: EA content 22.9% %, MAH fraction 3.4% by weight, melting point 78 ° C EH4: EA fraction 29.4% by weight, MAH fraction 2.6% by weight, melting point 68 ° C

In Comparative Example 4, a long-fiber nonwoven fabric comprising a sheath-core type composite filament using high-density polyethylene (sheath component) alone as the first component and polypropylene (core component) as the second component was used. Is shown.

A fluff pulp and a highly water-absorbent resin wrapped with the long-fiber nonwoven fabric of the present invention obtained in Examples 1 to 9 are covered with a back sheet made of a stretched film of linear low-density polyethylene and a cover made of tissue paper. An absorbent core layer made of a second sheet, a top sheet made of a nonwoven fabric heat-bonded by a through-air method made of short fibers of a sheath-core type composite fiber made of high-density polyethylene and a core component made of polypropylene, and laminated in this order. It was used as a second sheet of disposable diapers. In this case, the second sheet is thermally bonded to the cover (cover of the absorbent core layer) made of the cover sheet and the tissue paper by a number of point-like partial thermocompression processes. When the wearing test of the obtained disposable diaper was carried out, there was no lifting of the top sheet, the top sheet did not cling to the local area, there was no problem of clogging by the second sheet, the second sheet and the cover sheet and the cover of the absorbent core layer did not. A diaper having good adhesion was obtained.

[0065]

The long-fiber nonwoven fabric of the present invention contains at least 20% by weight of an ethylene-acrylate-maleic anhydride copolymer and forms at least a part of the fiber surface in the fiber length direction. The first component, comprising a heat-fusible conjugate long fiber having a crystalline thermoplastic resin having a higher melting point than the first component as a second component, containing at least a first component containing an inorganic powder, Content is 5 in fiber concentration
Since it contains from 0.00 to 50,000 weight ppm, it is possible to provide a long-fiber nonwoven fabric which is excellent in high adhesiveness and low-temperature adhesiveness, has good texture such as flexibility and touch, and is excellent in adhesiveness to different kinds of materials.

In the long-fiber nonwoven fabric of the present invention, ethylene-
By setting the copolymer composition of the acrylate-maleic anhydride copolymer in a preferred embodiment in which the maleic anhydride fraction is 2 to 5 wt% and the acrylate ester fraction is 6 to 30 wt%, the melting point is reduced. Neither is it too low to make melt composite spinning difficult, nor too sticky, it satisfies the necessary properties as a material constituting the fiber surface, and it has relatively good thermal stability Therefore, there are few problems of thermal decomposition and deterioration in melt spinning, and furthermore, it is excellent in thermal adhesion to other foreign materials, and it is possible to provide a long-fiber nonwoven fabric that can more preferably exert the above-mentioned effects.

In the long-fiber nonwoven fabric according to the present invention, the ethylene-acrylic acid ester-maleic anhydride copolymer has a preferred embodiment in which the melting point is 60 to 110 ° C., so that the spinnability is good and easy. It is preferable because a long-fiber nonwoven fabric can be obtained, and the obtained long-fiber nonwoven fabric has good adhesiveness.

In the long-fiber nonwoven fabric according to the present invention, the resin component of the first component is preferably a mixture of an ethylene-acrylate-maleic anhydride copolymer and polyethylene, so that polyethylene can be used. The combined use is preferable because friction with a metal such as air soccer described above during melt spinning can be further reduced and adhesion between fibers can be more appropriately prevented.

In the long-fiber nonwoven fabric of the present invention, the inorganic powder having an average particle diameter of 0.04 to 2 μm in the preferred embodiment has an average particle diameter of 0.04 to 2 μm. , The increase in cost is smaller than that of the smaller particle size, secondary aggregation of the inorganic powder, clogging of the filter and the spinning nozzle, and breakage of the yarn may occur, resulting in reduced operability. No, and compared to the case of using an inorganic powder having a larger particle size,
It is preferable because the dispersibility of the inorganic powder is not deteriorated, the filter and the spinning nozzle are not clogged, and the operability is not reduced due to the occurrence of yarn breakage.

In the long-fiber nonwoven fabric according to the present invention, the inorganic powder is preferably at least one inorganic powder selected from titanium dioxide, silica, alum, calcium carbonate, calcium oxide, magnesium oxide and talc. As a result, these inorganic powders have a relatively small nucleating effect and increase the crystallization temperature of the resin constituting the first component containing at least 20% by weight of the ethylene-acrylate-maleic anhydride copolymer. Hardly occurs, and the increase in crystallinity is extremely small.Therefore, characteristics such as flexibility and high adhesion of the resin having a low melting point or a low softening point as the first component, and low-temperature adhesion are hardly impaired. It is preferable because a long-fiber nonwoven fabric having good texture such as properties and touch and excellent adhesiveness with other foreign materials can be obtained.

In the long-fiber nonwoven fabric of the present invention, by adopting a preferred embodiment in which the crystalline thermoplastic resin of the second component is polypropylene, a relatively flexible long-fiber nonwoven fabric can be obtained, which is preferable.

In the long-fiber nonwoven fabric of the present invention, by setting the crystalline thermoplastic resin of the second component to a preferred embodiment in which polyethylene terephthalate is used, the strength is higher and the crimping property is improved. It is preferable because a long-fiber nonwoven fabric having more excellent elasticity (cushioning property) can be obtained.

In the long-fiber nonwoven fabric according to the present invention, by adopting a preferred embodiment in which the long-fiber nonwoven fabric is a long-fiber nonwoven fabric obtained by a spun bond method, the non-woven fabric having excellent mechanical properties such as tensile strength is obtained. Can be easily obtained, and the filaments obtained by melt-spinning can be spread and accumulated as they are to obtain a nonwoven fabric, so that the productivity is very excellent, and the nonwoven fabric with the above properties at a relatively low cost can be obtained. While being obtained, the above-mentioned effects are particularly effectively exhibited by the spunbonding method, and the conventional disadvantages of the composite long-fiber nonwoven fabric obtained by the spunbonding method can be effectively improved, which is preferable.

Further, the absorbent article of the present invention improves the adhesiveness without causing clogging or the like by using the long-fiber nonwoven fabric for at least a part of the absorbent article, and the absorbent article during use. Absorbent articles free from problems caused by peeling or collapse of the layer constituting can be provided.

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Claims (10)

[Claims] 1. A first component containing at least 20% by weight of an ethylene-acrylate-maleic anhydride copolymer and forming at least a part of the fiber surface in the length direction of the fiber; It is composed of a heat-fusible conjugate long fiber having a crystalline thermoplastic resin having a higher melting point than the component as a second component, and contains an inorganic powder in at least the first component, and the content of the inorganic powder is a fiber concentration. 500-50,000 weight pp
A long-fiber nonwoven fabric characterized by containing m. 2. A copolymer composition of an ethylene-acrylic acid ester-maleic anhydride copolymer having a maleic anhydride content of 2 to 5% by weight and an acrylic acid ester content of 6 to 30% by weight. 2. The long-fiber nonwoven fabric according to 1. 3. The long-fiber nonwoven fabric according to claim 1, wherein the ethylene-acrylate-maleic anhydride copolymer has a melting point of 60 to 110 ° C. 4. The long-fiber nonwoven fabric according to claim 1, wherein the resin component of the first component is a mixture of an ethylene-acrylate-maleic anhydride copolymer and polyethylene. 5. The long-fiber nonwoven fabric according to claim 1, wherein the inorganic powder has an average particle diameter of 0.04 to 2 μm. 6. An inorganic powder comprising titanium dioxide, silica,
The long-fiber nonwoven fabric according to any one of claims 1 to 5, which is at least one inorganic powder selected from alum, calcium carbonate, calcium oxide, magnesium oxide, and talc. 7. The long-fiber nonwoven fabric according to claim 1, wherein the crystalline thermoplastic resin of the second component is polypropylene. 8. The long-fiber nonwoven fabric according to claim 1, wherein the crystalline thermoplastic resin of the second component is polyethylene terephthalate. 9. The long fiber nonwoven fabric according to claim 1, wherein the long fiber nonwoven fabric is a long fiber nonwoven fabric obtained by a spun bond method. 10. An absorbent article using the long-fiber nonwoven fabric according to claim 1 for at least a part thereof.