JP2018104846A - Ultrafine fiber nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonwoven fabric made by an air-laid method, which is made of ultrafine fibers and suitably used as sanitary products, food absorption sheets and other absorbent articles.SOLUTION: An ultrafine fiber nonwoven fabric comprises 50-100 wt.% of ultrafine fibers having single fiber fineness of 0.05-0.5 dtex and at least one layer of nonwoven fabric with 3-50 g/mof fabric weight made by an air-laid method. The ultrafine fiber nonwoven fabric is a monolayer or multilayer excellent in moisture diffusion property with reduced wetback.SELECTED DRAWING: None

Description

  The present invention relates to an ultrafine fiber nonwoven fabric produced by an airlaid method mainly composed of ultrafine short fibers. More specifically, the present invention is mainly composed of an air-laid nonwoven fabric using ultrafine short fibers, is excellent in water diffusibility, has little wetback, is disposable, and is an absorbent article, such as an incontinence sheet for adults and babies, The present invention relates to an ultrafine fiber nonwoven fabric constituting a urine absorbing pad, a disposable diaper, a feminine sanitary product, a cage sheet, a breast milk pad and the like. In particular, the present invention uses an ultra-fine fiber nonwoven fabric used in a cage sheet that absorbs and retains water-based excrement such as urine, menstrual blood, and cages, and a light incontinence absorbent sheet, and further uses such an ultra-fine fiber nonwoven fabric The present invention relates to absorbent articles and absorbent sheets for food.

Absorbent articles such as those described above are generally required to have various quality performances. The required performance includes absorption performance that quickly leads urine and menstrual blood to the absorption layer, and reversal of the liquid retained in the absorption layer (wet back). ) Prevention, touch, softness, moisture prevention, rash prevention and other comfort maintenance, and feeling of use.
In order to improve the quality issues of these absorbent articles, there are often a second sheet between the top sheet and the absorber, and a sheet (third sheet) using water absorbent paper between the absorber and the back sheet. Proposed and put into practical use.

For example, in Patent Document 1 (International Publication WO01 / 054640 pamphlet), as a temporary water storage layer (that is, a second sheet) made of a nonwoven fabric having a basis weight of 20 to 100 g / m ² , a heat-meltable fiber and a rayon fiber (10% or more) An air-through nonwoven fabric made from the above is shown, but specific contents such as fineness and layer structure are not shown, and there is no description or suggestion about the air-laid nonwoven fabric using the ultrafine fibers of the present invention. In addition, since rayon fibers absorb moisture, the rayon fibers are liable to give moisture to the skin through the surface sheet, and have a problem that stuffiness is likely to occur. Further, Patent Document 1 also describes that a water absorbent paper (third sheet) is interposed between the absorber and the back sheet. However, in the water absorbent paper, the liquid retained in the absorbent layer is not completely reversed. It cannot be prevented. That is, when water absorbent paper is used as a third sheet between the absorbent sheet and the back sheet, it is difficult to completely prevent liquid leakage to the back sheet.

Patent Document 2 (Japanese Patent Publication No. 2007-500048) proposes a capturing member (that is, a second sheet) made of regular polyester fibers, spiral crimped polyester fibers, and a latex binder. However, since the fibers are thick, the touch is not good, and since they are chemical bonds, residual monomers and trace formalin may be generated, which is not preferable from the viewpoint of safety and safety.
Further, Patent Document 3 (Japanese Patent Laid-Open No. 11-81116) proposes an airlaid nonwoven fabric composed of short fibers having a length of 3 to 25 mm used for sanitary materials, but should be an absorbent article. There is no description or suggestion about fineness, layer structure, hydrophilicity, moisture migration (diffusibility), etc.

International publication WO01 / 054640 pamphlet Special table 2007-500048 gazette JP-A-11-81116

  The present invention relates to a moisture diffusibility that is suitably used as sanitary products, sanitary napkins, cage sheets, paper diapers, and other absorbent articles, particularly as cage sheets, light incontinence diffusion sheets, and food absorbent sheets. An object of the present invention is to provide an ultra-fine fiber nonwoven fabric that is excellent in low wetback.

  The inventors of the present invention focused on an airlaid method nonwoven fabric in which fibers are easily arranged not only in the vertical and horizontal directions but also in the thickness direction, and as a result of intensive studies on the optimum structure, the ultrafine fibers having a specific single yarn fineness were obtained. When using these short fibers, we find diffusivity under low absorption, especially in the case of a cage sheet, and further optimize their formulation and composition to achieve water diffusivity that has effective performance and practicality for this application. It has reached the technology of ultra-fine fiber nonwoven fabric with excellent wetback.

That is, this invention is comprised from following (1)-(12).
(1) 50 to 100% by weight of ultrafine fibers having a single yarn fineness of 0.05 to 0.5 dtex and a fiber length of 2 to 15 mm, 50 to 0% by weight of other fibers or pulp, and a basis weight of 3 to 50 g / An ultrafine fiber nonwoven fabric (hereinafter also simply referred to as “nonwoven fabric”) containing at least one layer of m ² airlaid nonwoven fabric.
(2) The ultrafine fiber nonwoven fabric according to (1), wherein another nonwoven fabric including an airlaid nonwoven fabric is laminated on at least an upper layer and / or a lower layer of the nonwoven fabric according to (1).
(3) The ultrafine fiber nonwoven fabric according to (1) or (2), which has a multilayer structure and each layer is integrated by an airlaid method.
(4) The ultrafine fiber nonwoven fabric according to any one of (1) to (3), wherein the ultrafine fiber is a thermoadhesive conjugate fiber.
(5) The ultrafine fiber is composed of at least one fiber-forming thermoplastic resin selected from the group of polyolefin resin, polyester resin, and polyamide resin, and the melting point of the thermoplastic resin of the core component is the sheath component The ultrafine fiber nonwoven fabric according to any one of claims 1 to 4, which is a core-sheath type thermoadhesive conjugate fiber having a melting point higher than that of the thermoplastic resin.
(6) The heat-adhesive conjugate fiber is a core-sheath type conjugate fiber using a polypropylene polymer for the core and a polyolefin polymer having a melting point lower than that of the polypropylene polymer for the sheath, and the single yarn fineness is 0. The ultrafine fiber nonwoven fabric according to (5), which is 1 to 0.3 dtex.
(7) The ultrafine fiber nonwoven fabric according to any one of (1) to (6), wherein the nonwoven fabric is embossed and punched.
(8) An absorbent article using the ultrafine fiber nonwoven fabric according to any one of (1) to (7) above.
(9) The absorbent article according to (8), wherein the following (a) to (d) are sequentially laminated.
(A) A top sheet made of a nonwoven fabric having a single yarn fineness of 1 to 3 dtex, a thermal bond nonwoven fabric or an airlaid nonwoven fabric, and a basis weight of 10 to 30 g / m ² .
(B) A second sheet comprising 50 to 100% by weight of fibers having a single yarn fineness of 2 to 20 dtex, a thermal bond nonwoven fabric or an airlaid nonwoven fabric, and a nonwoven fabric having a basis weight of 10 to 60 g / m ² .
(C) The ultrafine fiber nonwoven fabric according to any one of (1) to (7) above.
(D) A back sheet made of a film.
(10) An absorbent sheet for foods using the ultrafine fiber nonwoven fabric according to any one of (1) to (7) above.
(11) The absorbent sheet for food according to (10), wherein the ultrafine fiber nonwoven fabric according to any one of (1) to (7) is laminated on a porous film (perforated film).
(12) A wiper, a face mask, a fragrance volatile material, a pet sheet, or a filter using the ultrafine fiber nonwoven fabric according to any one of (1) to (7) above.

The ultra-fine fiber nonwoven fabric of the present invention is mainly composed of a non-woven fabric based on an airlaid method mainly composed of ultra-fine fibers having a single yarn fineness of 0.05 to 0.5 dtex and a fiber length of 2 to 15 mm. Since the fibers are thin and are bonded by heat by the airlaid method, moisture is diffused very well as a sheet. Further, in an absorbent article using the ultra-fine fiber nonwoven fabric by the airlaid method mainly composed of the ultra-fine fiber of the present invention on the lower layer side, the fineness is usually narrower than that of the upper layer side, so the gap between the fibers is small and it is difficult to retain moisture. Therefore, it moves to the absorber side promptly, and so-called wetback (the absorbed excretory fluid oozes out to the surface) is very little. When the nonwoven fabric mainly composed of the ultrafine fibers of the present invention is used as, for example, a second sheet (or intermediate sheet) of an absorbent article, the airlaid nonwoven fabric of the present invention using the ultrafine fibers mainly composed of the nonwoven fabric of the present invention has a fineness. However, when the absorbent is disposed in the upper layer or the lower layer, the moisture that has entered the surface layer is drawn by capillarity and transferred to the absorber in contact therewith. In addition, when the ultrafine fiber nonwoven fabric according to the airlaid method of the present invention is used as a third sheet by being disposed between a backsheet made of an absorbent body and a moisture permeable film, the water stored in the absorbent body is the present invention. It is difficult to wet back to the ultrafine fiber nonwoven fabric side, and the performance as a diaper can be improved.
In addition, when the above-mentioned ultrafine fiber contains a heat-adhesive conjugate fiber, it is possible to make a nonwoven fabric with 100% ultrafine fiber by the thermal bond method, and sufficiently exhibit the water diffusibility by the ultrafine fiber and the moisture transfer to the absorber. Is desirable.
In addition, the nonwoven fabric of the present invention can also be applied to food absorbent sheets other than absorbent articles, for example, food trays. In this case, the fineness of the layer of ultrafine fibers (airlaid nonwoven fabric mainly composed of ultrafine fibers) However, it is possible to keep the freshness of fresh fish and meat, which are food materials, with very little wet-back on the surface layer by drawing water that has entered the surface layer by capillary action.
As described above, since the nonwoven fabric base of the present invention is composed of an airlaid nonwoven fabric mainly composed of ultrafine fibers, urine, menstrual blood, orimono, soft stool, fresh fish, and meat that penetrates from the surface sheet. A structure (such as absorbent articles and foods) that diffuses liquids mainly composed of drip, etc. in the direction of the area, makes use of the capacity of the absorber over a wide area, quickly shifts to the absorber, and is difficult to wet back. Absorbent sheet etc.) can be provided.

It is an electron micrograph (500 times) of the surface of the airlaid nonwoven fabric I using the extra fine fiber of Example 6 of this invention.

The nonwoven fabric of this invention is used suitably as a diffusion sheet in an absorbent article. When the non-woven fabric of the present invention is used for a diffusion sheet, particularly when a heat-adhesive conjugate fiber that does not absorb moisture is a main component, the fiber itself does not entrap moisture, and the fiber is thin and the space between fibers is reduced by the airlaid method. Since it is bonded by heat, it exhibits the effect of diffusing moisture as a sheet, so that the entire product can be effectively used as an absorbent, and there is little wetback and it is difficult to stuffy. In addition, since the fineness is thin, there is an effect that water that has entered the surface layer is drawn by capillary action and transferred to the absorber in contact therewith. Therefore, by using the nonwoven fabric excellent in moisture diffusibility of the present invention and having little wetback as a diffusion sheet between the top sheet and the absorbent body of the absorbent article or between the absorbent body and the back sheet, While diffusing liquid mainly consisting of urine, menstrual blood, orimono (and in the case of a food absorbent sheet, drip of fresh fish or meat) in the direction of the area, quickly transfer it to the absorber, In addition, the absorbent article (and the absorbent sheet for foods) is difficult to wet back.
Hereinafter, the air-laid nonwoven fabric, the other nonwoven fabric, the film and the like which are composed of the ultrafine fibers constituting the nonwoven fabric of the present invention will be described.

<Airlaid nonwoven fabric>
The airlaid nonwoven fabric used as the base material constituting the nonwoven fabric of the present invention is obtained by an airlaid method containing 50 to 100% by weight of ultrafine fibers and 50% by weight or less of other fibers or pulp and having a basis weight of 3 to 50 g / m ^2. It is an ultra-fine fiber nonwoven fabric.

Extra fine fiber:
The ultrafine fibers constituting the air-laid nonwoven fabric used as the base material of the nonwoven fabric of the present invention have a single yarn fineness of 0.05 to 0.5 dtex, preferably 0.1 to 0.3 dtex, and a fiber length of 2 to 15 mm, preferably 3 It is an ultrafine short fiber of ˜7 mm.
Here, when the single yarn fineness is less than 0.05 dtex, normal melt spinning is difficult, and the productivity of the fiber is remarkably inferior. On the other hand, when it exceeds 0.5 dtex, moisture is not attracted to the obtained nonwoven fabric. The effect of diffusing moisture is reduced.
In addition, the ultrafine fiber used in the present invention has a good fiber opening property when it is short, and it tends to be a more uniform nonwoven fabric. However, when it is less than 2 mm, it is close to a powder form, and it is difficult to make a network structure by interfiber bonding. Or, the strength as a non-woven fabric is low, and it is not preferable because it lacks practicality. On the other hand, if the length is longer than 15 mm, the strength of the nonwoven fabric increases, but the fibers tend to get entangled during pneumatic transportation of the fibers during the production of the nonwoven fabric, which increases the fiber lump defects, which is not preferable.

Examples of the ultrafine fiber material include polyolefin fiber, polyester fiber, polyamide fiber, acrylic fiber, rayon fiber, acetate fiber, etc., preferably polyolefin composite fiber and polyester composite fiber, particularly polyolefin composite fiber. Is preferred.
As the polyolefin-based composite fiber, a polyolefin-based core-sheath type composite fiber using a polypropylene-based polymer for the core and a polyolefin-based polymer having a melting point lower than that of the polypropylene-based polymer for the sheath is particularly preferably used.

Polyolefin-based sheath-core composite fiber:
The polyolefin core-sheath type composite fiber used in the present invention is, for example, a melt-spun composite having a polypropylene polymer as a core component and a polyolefin polymer having a melting point lower than that of the polypropylene polymer as a sheath component. Examples thereof include short fibers obtained by drawing and cutting undrawn yarn.

As the polypropylene polymer used for the core component of the composite fiber, an isotactic polypropylene resin is preferably used.
The polypropylene resin may be a polypropylene homopolymer or a copolymer of propylene and an α-olefin (for example, ethylene, butene-1, etc.).

That is, as the polypropylene-based polymer, for example, isotactic propylene homopolymer, ethylene-propylene random copolymer having a low ethylene unit content, a homo part composed of a polypropylene homopolymer, and a relatively high ethylene unit content. A propylene block copolymer composed of a copolymer part composed of many ethylene-propylene random copolymers, and each homo part or copolymer part in the propylene block copolymer is further an α-olefin such as butene-1 Examples thereof include crystalline propylene-ethylene-α-olefin copolymers formed by copolymerization of
The melt index MI (temperature 230 ° C., load 21.18 N) of the polypropylene polymer constituting the core component is preferably in the range of 70 to 170 g / 10 minutes.

On the other hand, the polyolefin polymer having a melting point lower than that of the polypropylene polymer constituting the sheath component of the composite fiber of the present invention includes, for example, ethylene such as high density, medium density, low density polyethylene and linear low density polyethylene. -Based polymers, copolymers of polypropylene and other α-olefins, specifically, propylene-butene-1 random copolymers, propylene-ethylene-butene-1 random copolymers, or non-crystalline such as soft polypropylene And the like, and poly (4-methylpentene-1). These polyolefin polymers may be used alone or in combination of two or more. Among these, high-density polyethylene is particularly preferable from the viewpoint of strength.
The melt index MI (temperature 230 ° C., load 21.18 N) of the polyolefin polymer used as the sheath component is preferably in the range of 60 to 90 g / 10 minutes.

  The ratio of the sheath component to the core component in this composite fiber is not particularly limited, but the weight ratio is preferably in the range of 3: 7 to 7: 3, more preferably 4: 6 to 6: 4, particularly 5: 5. Or its vicinity is preferable.

  The polyolefin composite fiber used in the present invention can be obtained by subjecting the polyolefin composite undrawn yarn to a drawing treatment and a cutting treatment. The stretching method may be any method as long as the stretched composite fiber having the above physical properties can be obtained, but the specific production method is detailed in, for example, Japanese Patent No. 5938149.

Other fibers, pulp:
The air-laid nonwoven fabric of the present invention may contain 50% by weight or less of other fibers and pulp in addition to the ultrafine fibers.

Here, as other fibers, for example, semi-synthetic fibers such as acetate, synthetic fibers such as polyester, polypropylene, polyamide, and vinylon, natural fibers such as cotton and hemp, and regenerated fibers such as rayon may be included. In this case, if the amount of other fibers exceeds 50% by weight, there is a greater possibility that the other fibers will fall off, and the wet strength may be lowered, which causes a practical problem.
The single yarn fineness of other fibers is usually 1 to 30 dtex, preferably 1.5 to 10 dtex, and the fiber length is the same as the fiber length of the above-mentioned ultrafine fiber.

Further, the pulp is used in the nonwoven fabric of the present invention to exhibit the property of having a water absorption effect and high water retention. In the airlaid nonwoven fabric, pulp is usually used by pulverizing sheet-like pulp.
However, the amount of pulp used is 50% by weight or less, preferably 30% by weight or less. If it exceeds 50% by weight, a phenomenon in which the wetback is deteriorated by water retention of the pulp itself is not preferable.
In any case, if the number of absorbent fibers such as pulp, cotton, rayon, etc. increases, it is not desirable because moisture diffusibility and moisture transfer to the absorber cannot be sufficiently exhibited by the ultrafine fibers of the present invention.

Weight per unit:
The basis weight of the air-laid nonwoven fabric that is the base material of the nonwoven fabric of the present invention is 3 to 50 g / m ² , preferably 10 to 30 g / m ² . If it is less than 3 g / m ^2, it is too thin to increase the liquid return (wet back), and it is difficult to produce a sheet in production. On the other hand, if it is larger than 50 g / m ^2, it is too thick, so that the phenomenon of retaining water in the inter-fiber gap is strengthened, so that liquid return (wet back) is deteriorated and economic efficiency is deteriorated.

Manufacturing airlaid nonwovens;
The airlaid nonwoven fabric mainly composed of the ultrafine fibers of the present invention is produced by the airlaid method. The nonwoven fabric produced by the airlaid method is preferred because the fibers forming the nonwoven fabric are randomly three-dimensionally oriented in the longitudinal direction, width direction and thickness direction of the nonwoven fabric.
The ultrafine fibers forming the air-laid nonwoven fabric of the present invention are preferably polyolefin core-sheath composite fibers, which are thermally bonded by heat treatment and fixed to the nonwoven fabric sheet in a network structure by interfiber bonding.

Here, the air-laid nonwoven fabric sheet according to the present invention can be obtained as follows.
That is, a predetermined amount of defibrated heat-adhesive ultrafine fibers (heat-adhesive ultrafine synthetic fibers, such as polyolefin core-sheath composite ultrafine fibers) and, if necessary, pulp and other fibers as main components, The fibers blown out from the pores provided in the discharge section are dropped into a metal or plastic fiber collection net installed in the lower part, and air is suctioned at the lower part of the net. However, the fiber is deposited on the net, and this operation is repeated at least once as necessary. In addition, the said ultra fine fiber can also use the ultra fine fiber which does not have heat adhesiveness.
Next, the nonwoven fabric sheet of the present invention can be obtained by heat-treating the whole to a temperature at which the heat-adhesive conjugate fiber sufficiently exhibits its adhesive effect. In order to sufficiently exert the adhesive effect, heat treatment is generally required at a temperature 5 to 40 ° C. higher than the melting point of the adhesive component (that is, the sheath portion) of the ultrafine fiber fiber.

In addition, functional processing, such as a deodorizer, an antibacterial agent, a fragrance | flavor, a moisturizer, a coloring agent, a hydrophilic agent, a water repellent, can also be provided to the nonwoven fabric sheet of this invention. Examples of the processing method include a method in which fibers having these functions are mixed in advance, a powdery agent is mixed, and a liquid agent is sprayed or impregnated.
Thus, the nonwoven fabric sheet manufactured by the airlaid method can three-dimensionally orient the fibers randomly in the flow direction, the width direction, and the thickness direction of the nonwoven fabric. In particular, the fiber arrangement in the thickness direction contributes to the moisture permeation performance. And since these are thermally bonded, delamination does not occur. Moreover, since the non-woven sheet manufactured by the airlaid method has good uniformity, there is less variation in performance.

The air-laid nonwoven fabric constituting the nonwoven fabric of the present invention can be embossed, drilled or the like as necessary.
In these processes, in the case of embossing, the diffusibility of moisture in the horizontal direction is improved, and in the case of drilling, the effect of improving the migration of moisture in the vertical direction is achieved.

The nonwoven fabric of the present invention is based on the airlaid nonwoven fabric as described above, and other nonwoven fabrics and / or films may be laminated on the upper layer and / or lower layer of the nonwoven fabric.
As an embodiment of the nonwoven fabric in this invention, absorbent articles, such as a diaper, and the absorption sheet for foodstuffs are mentioned.
Hereinafter, the absorbent article and the absorbent sheet for food will be described separately.

<Absorbent article>
The nonwoven fabric of the present invention is used as an absorbent article by combining another nonwoven fabric and / or film with the upper layer and / or the lower layer of the above airlaid nonwoven fabric.
Below, the structure of an absorbent article is divided and demonstrated.
In addition, in absorbent articles such as diapers, (a) a top sheet, (b) a second sheet, (c) an absorbent sheet, and (d) a back sheet are sequentially laminated in order from the human body side. Or, in addition to these, (e) a third sheet is interposed between the absorber sheet and the back sheet, and these materials are integrally bonded and integrated by fixing means such as stitching. .
The air-laid nonwoven fabric of the present invention can be used as these top sheet, second sheet, absorber sheet or third sheet, and the nonwoven fabric of the present invention contains at least one layer of the air-laid nonwoven fabric of the present invention. Therefore, the non-woven fabric of the present invention should be construed to include the following absorbent articles when including at least one layer of the air-laid non-woven fabric of the present invention.

(A) Topsheet Here, the nonwoven fabric sheet of the present invention used for the topsheet is mainly composed of heat-adhesive synthetic fibers and has a basis weight of 10 to 30 g / m ² , preferably 15 to 20 g / m ² . Or it is comprised from the thermal bond nonwoven fabric (air through system).
Here, “main component” means that the heat-adhesive synthetic fiber is 70% by weight or more, preferably 85% by weight or more, and about 30% by weight or less of other fibers and pulp described later. It may be included.
In addition, the nonwoven fabric sheet used for the top sheet of the present invention is mainly composed of heat-adhesive synthetic fibers. In addition to those using 100% by weight of the heat-adhesive synthetic fibers, for example, heat-adhesive synthetic fibers + pulp You may be comprised from the one or more nonwoven fabric which consists of fiber or a heat bondable synthetic fiber + pulp fiber + chemical binder.
In particular, from the viewpoint of sheet strength and wetback prevention, it is preferable that the sheet is composed only of heat-bonding synthetic fibers. Moreover, in order to hold | maintain highly viscous excrement, such as menstrual blood, a stool, or loose stool, what contains about 30 weight% or less of hydrophilic fibers, such as a pulp, is also a preferable aspect.

  Here, the heat-adhesive synthetic fiber in the present invention may be anything as long as it is melted by heat and bonded to each other, and the nonwoven fabric itself is fixed in a network structure by the inter-fiber bond. Examples of such heat-adhesive synthetic fibers include polyolefins grafted with polyolefins, unsaturated carboxylic acids, fibers obtained from biodegradable resins such as polyesters, polyvinyl alcohol, and polylactic acid. Can be mentioned.

  As such a heat-bonding synthetic fiber, a core-sheath type or an eccentric side-by-side type composite fiber is suitable. Examples of the low melting point adhesive component constituting the sheath or the outer periphery of the fiber include polyolefins such as polyethylene, polypropylene, and ethylene / propylene copolymers, and low melting point copolymer polyesters. The polymer constituting the core component or the inner fiber layer is preferably a polymer having a melting point higher than that of the sheath and not changing at the heat bonding treatment temperature. As such a combination, for example, the sheath / core may be polyethylene / polypropylene, polyethylene / polyester, polypropylene / polyester, low-melting copolymer polyester / polyester, and the like. These polymers may be modified as long as they do not impair the action / effect of the present invention.

  When the heat-adhesive synthetic fiber is thin, the number of constituent fibers is increased and the fiber interval is reduced, so that the concealability required for the use of the absorbent article is improved, and the texture and the touch are also softened. If it is thick, the gap between the fibers is increased and the air permeability is improved, so that an increase in humidity in the vicinity of the skin is suppressed, and an effect of reducing the feeling of stuffiness can be expected. Therefore, the fiber thickness of the top sheet may be selected according to the application, but the preferable single yarn fineness is 0.5 to 5 dtex, more preferably 1 to 3 dtex. If it exceeds 5 dtex, the resulting non-woven fabric sheet becomes hard and unpleasant to the touch or irritation to the skin increases. On the other hand, if it is less than 0.5 dtex, the fineness is too small and the resulting nonwoven fabric is less bulky, and the space for holding a highly viscous liquid such as menstrual blood, vaginal discharge, or loose stool is reduced, which is not preferable.

  Further, the length of the heat-adhesive synthetic fiber is preferably 2 to 15 mm in the air-laid nonwoven fabric. If the fibers are short, the spreadability is improved and a more uniform non-woven fabric tends to be obtained. However, if the fiber is less than 2 mm, it approaches a powder form, making it difficult to form a network structure by bonding between fibers, and the strength as a non-woven fabric is reduced. It is not preferable because it lacks properties. On the other hand, if the length is longer than 15 mm, the strength of the nonwoven fabric increases, but the fibers tend to become entangled during pneumatic transportation of the fibers during the production of the nonwoven fabric, which increases the fiber mass defects, which is not preferable. Particularly preferred is 3 to 7 mm.

  In addition to the above heat-adhesive synthetic fibers, the nonwoven sheet used in the top sheet of the present invention includes recycled fibers such as rayon, semi-synthetic fibers such as acetate, synthetic fibers such as polyester, polypropylene, polyamide, and vinylon, pulp Other fibers such as natural fibers such as cotton and hemp may be included. In this case, the proportion of the heat-adhesive synthetic fiber in the nonwoven fabric sheet is preferably 70 to 100% by weight, more preferably 85 to 100% by weight. If the amount is less than 70% by weight, the above-mentioned other fibers may drop off, and the wet strength may be lowered.

  As the heat-adhesive synthetic fiber, any fiber can be used as long as it is melted by heat and bonded to each other, and examples thereof include fibers such as polyolefins, polyesters, and polyvinyl alcohol. It is more preferable. As a method for hydrophilizing the fiber, there are a method of kneading a hydrophilic drug into the fiber, a method of coating a fiber surface with a hydrophilizing agent, and the like. Further, a non-woven sheet used for a sheeted top sheet may be subjected to a hydrophilic treatment using a general method. In the case of a sheet using water-repellent and hydrophobic fibers, the absorption of the liquid component and the transfer performance to the lower layer are poor, and it becomes easy to cause lateral leakage, and therefore, fibers subjected to hydrophilic treatment are preferable.

Here, as the hydrophilizing agent, for example, a sulfonic acid metal salt compound such as disclosed in JP-A-10-325060, for example, sodium alkyl sulfonate, etc., a hydrophilizing aid such as ethylene bis fatty acid amide, etc. The method of kneading with is mentioned. In the case of kneading into a composite fiber, it may be kneaded only into the polymer that forms the fiber surface.
In addition, as the hydrophilic treatment on the fiber surface, there are a general hydrophilic treatment with a temporary initial hydrophilic property and a durable hydrophilic treatment that can withstand bodily fluid excretion. A general surfactant may be used for the general hydrophilic treatment. Further, in the durable hydrophilization treatment, for example, as shown in JP-A-62-19165 and JP-A-2000-256965, hydrophilic group-containing polyester oligomer, sulfoisophthalate sodium salt, It is preferable to use an ether polyester block copolymer, a polyoxyalkylene glycol derivative, and the like, and after applying the surface, a heat treatment is applied to form a partial bond between the polymer that forms the fiber surface and the treatment agent.

These fibers forming the non-woven sheet used in the top sheet of the present invention are thermally bonded, and the non-woven sheet is fixed in a network structure by bonding between the fibers.
The nonwoven fabric sheet used for the top sheet of the present invention has a basis weight of 10 to 30 g / m ² , preferably 15 to 20 g / m ² . If it is less than 10 g / m ² , the strength of the nonwoven fabric is lowered, and production problems such as the suitability of nonwoven fabric production and the suspension of the production line due to insufficient tensile strength in the actual diaper production line are likely to occur. On the other hand, when it exceeds 30 g / m ² , the sheet becomes hard, causing a problem of absorption and lowering of the migration performance to the lower layer.

  The nonwoven fabric sheet used for such a top sheet of the present invention is preferably produced by the airlaid method. The nonwoven fabric produced by the airlaid method is preferable because the fibers forming the nonwoven fabric are randomly three-dimensionally oriented in the longitudinal direction, width direction and thickness direction of the nonwoven fabric, but are not limited thereto. A thermal bond nonwoven fabric (air-through method) may be used.

Here, the nonwoven fabric by the airlaid method which concerns on this invention can be obtained as follows.
That is, a fiber having a predetermined amount of defibrated thermoadhesive synthetic fiber as a main component is conveyed while being uniformly dispersed in an air stream, and the fiber blown out from the pores provided in the discharge unit is installed in the lower part. Deposit on a metal or plastic fiber collection net and repeat this operation at least once as needed.
For example, when depositing a plurality of times, the second and subsequent web depositions are similarly deposited on the deposition sheet.
Next, the nonwoven fabric of the present invention can be obtained by heat-treating the whole to a temperature at which this heat-adhesive synthetic fiber sufficiently exhibits its adhesive effect. In order to sufficiently exert the adhesive effect, heat treatment is generally required at a temperature 5 to 40 ° C. higher than the melting point of the adhesive component of the heat-adhesive synthetic fiber.

  In addition, functional processing, such as deodorizing, antibacterial, aroma, moisture retention, coloring, and hydrophilicity, can also be given to the top sheet (nonwoven fabric sheet) of the present invention. Examples of the processing method include a method in which fibers having these functions are mixed in advance, a powdered drug is mixed, and a liquid drug is sprayed or impregnated.

  Thus, the nonwoven fabric manufactured by the airlaid method can three-dimensionally orient the fibers at random in the flow direction, width direction and thickness direction of the nonwoven fabric. And since these are thermally bonded, delamination does not occur. Moreover, since the non-woven fabric produced by the airlaid method has good uniformity, there is less variation in performance.

Next, the nonwoven fabric sheet used for the top sheet of the present invention can be obtained by heat-treating the entire fiber web at a temperature 5 to 40 ° C. higher than the melting point of the adhesive component of the heat-bonding synthetic fiber.
A specific example of this heat treatment is hot air treatment. For example, the hot air treatment for forming the fiber-to-fiber bond includes a melting point higher than the melting point of the low melting point component of the thermoadhesive conjugate fiber (the sheath component of the core-sheath type conjugate fiber or the low melting point component of the side-by-side type conjugate fiber). Temperature is needed. However, if the melting point is 30 ° C. or higher than the melting point of the low melting point component, or the melting point of the high melting point component (the core component of the core-sheath type composite fiber or the high melting point component of the side-by-side type composite fiber), the heat shrinkage of the fiber. Is not preferable because it tends to be large and deteriorates the texture. Accordingly, the hot air treatment temperature is generally 110 to 200 ° C, preferably 120 to 180 ° C.

Furthermore, the nonwoven fabric sheet used for the top sheet of the present invention is the nonwoven fabric sheet and other nonwoven fabrics, such as thermal bonds, spunlaces, chemical bonds, spunbonds, melt blows, wet nonwoven fabrics, plastic nets, woven and knitted fabrics, cold koji, cocoons, etc. It may be a complex. As a means for compounding, a method that does not impair the gist of the present invention, such as hot melt, chemical bond, powder bond, calendar, and dot embossing, may be appropriately selected.
In this case, the nonwoven fabric other than the nonwoven fabric sheet of the present invention used for the composite can also be used as the second sheet in the absorbent article of the present invention.

In addition, as the (a) top sheet, an air laid nonwoven fabric made of the ultrafine fibers of the present invention can be used.
In this case, when the airlaid nonwoven fabric made of the ultrafine fibers of the present invention is used for the top sheet, it is preferable to perform a hydrophilic treatment as described above.

(B) Second sheet:
The second sheet is located between the top sheet made of the above nonwoven sheet and the absorbent sheet, prevents scattering of pulverized pulp and superabsorbent polymer, and removes solids in loose stool when loose stool occurs. In addition, it has a function of quickly transferring the liquid component to the absorption layer. Moreover, it has the absorption retention performance of the temporary liquid until it passes excretion liquid to an absorption layer.
As the second sheet, crepe paper, a thermal bond nonwoven fabric (air-through method), or a nonwoven fabric produced by an air-laying method using a heat-adhesive synthetic fiber having a single yarn fineness of 2 to 20 dtex, preferably 5 to 10 dtex is used. However, it is not limited to these. When using a heat-bonding synthetic fiber, the proportion of the synthetic fiber is preferably 50 to 100% by weight.
Basis weight of the second sheet is preferably 10 to 60 g / m ^2, more preferably a 20 to 40 g / m ^2. If the basis weight exceeds 60 g / m ² , the excretion liquid in high viscosity liquid such as menstrual blood, vaginal discharge, or loose stool is likely to stay in the second sheet until it passes through the top sheet and is absorbed by the absorbent layer. It is not suitable because it does not perform the function of delivering liquid to the absorbent layer. On the other hand, if the basis weight is less than 10 g / m ^2, it is not suitable because it is inferior in the temporary absorption retention performance of the liquid. As the second sheet, in addition, hydrophilic synthetic fibers such as polyethylene, polypropylene, polyethylene terephthalate and the like, or hydrophilic fibers such as rayon fibers and cellulose fibers such as pulp fibers are used alone. One or more non-woven fabrics may be mentioned which are bonded by heat fusion or adhesive, or which do not use an adhesive. Moreover, hydrophilic sheets such as crepe paper can also be mentioned.

In addition, as the (b) second sheet, an airlaid nonwoven fabric made of the ultrafine fibers of the present invention can be used.
In this case, when the air-laid nonwoven fabric made of the ultrafine fibers of the present invention is used as a second dose, it is preferable to perform a hydrophilic treatment as described above.

(C) Absorbent sheet The absorbent sheet that is directly opposite to the second sheet is for holding urine, menstrual blood, vaginal discharge, or excrement in loose stool, and is mainly composed of pulverized pulp, pulverized pulp, for example. Mixtures with superabsorbent polymer particles, crepe paper and / or paper with superabsorbent polymer supported in sheets can be used.

Here, the pulverized pulp is a pulp fiber having a fiber length of 5 mm or less obtained by defibrating a chemical pulp sheet or a mechanical pulp sheet with a pulverizer. Pulp raw materials are not limited to coniferous trees, but may include hardwood, straw, bamboo, kenaf, and the like, which can be appropriately selected and used.
In the case of a mixture of superabsorbent polymer particles mainly composed of pulverized pulp in the absorbent layer, the pulverized pulp and superabsorbent polymer and optionally a heat-fusible substance or chemical binder are uniformly mixed to form a mat. In addition, the one in which the apparent density of the absorbent layer itself is adjusted by an embossing roll or a hot press roll is used. The absorbent layer may be further wrapped with a hydrophilic sheet such as tissue paper from cellulose fibers or a hydrophilic nonwoven sheet made of synthetic fibers. When a heat-fusible substance is used, it is preferably added at 3 to 60% by weight based on the weight of the absolutely dry cotton-like pulp.

In addition, as a superabsorbent polymer, a well-known thing can be used for this invention as it is, and since the polyacrylic-acid type particle | grains absorb the excretion fluid 20 times or more of own weight, it is suitable. Such a superabsorbent polymer is used in an amount of 10 to 200% by weight, preferably 15 to 150% by weight, based on the weight of the dry pulverized pulp. The superabsorbent polymer has a high polymer such as menstrual blood, stool, or loose stool. When the excretory fluid in the viscous excreta is absorbed and swollen, the particles are kept from interfering with each other to the minimum, thereby allowing the excretory fluid to pass through 3 without contacting itself and forming a permeation barrier. It is distributed in cotton-like pulp so that it can permeate and absorb in dimension. The heat-fusible substance is preferably a fibrous material so that it can be mixed with pulverized pulp, and known materials such as polypropylene, polyethylene, and polyester resin are used as they are. From the viewpoint of strength, a core-sheath type composite fiber composed of two or more components of the resin is preferable. These heat-fusible substances are mixed together with pulverized pulp and a superabsorbent polymer to form a mat, and are thermocompression-bonded to form a structure having a skeleton. As the hydrophilic sheet, for example, known paper such as tissue paper, absorbent paper, hydrophilic non-woven fabric from cellulose fibers can be used for the present invention.
Depending on the purpose, the absorbent layer varies depending on whether it is used alone, a plurality of laminated layers, or another absorbent is used in combination, but generally the weight per unit area is 50 to 200 g / m ² .

(C) Specifically, the absorbent sheet includes (1) 10 to 90% by weight of the pulp and 90 to 10% by weight of the heat-adhesive synthetic fiber, and has a basis weight of 50 to 100 g / m ² . Nonwoven fabric, or (2) An absorber sheet containing 30 to 70% by weight of the polymer absorbent and 70 to 30% by weight of the thermoadhesive synthetic fiber and having a basis weight of 100 to 200 g / m ² is preferably used. It is done.

A hot melt adhesive or starch is used between the top sheet and the second sheet, between the second sheet and the absorber sheet, between the absorber sheet and the third sheet, and between the third sheet and the back sheet described later. Alternatively, it may be bonded partially or entirely with a water-soluble adhesive such as carboxymethylcellulose.
Further, the top sheet to the absorber sheet or the top sheet to the back sheet may be bonded by point bonding or line bonding by heat welding or high frequency processing.
In addition, when the amount of absorption is not so necessary, such as a cage sheet or a light incontinence diffusion sheet, the (c) absorbent sheet can be omitted, and the air-laid nonwoven fabric made of the ultrafine fibers of the present invention can also be used. .

(D) Back sheet A back sheet is usually attached to the back side of the absorbent article of the present invention. The back sheet is generally a liquid impermeable sheet, and for example, a plastic sheet such as a moisture permeable film or a non-woven fabric can be used. Moreover, the back sheet may or may not have air permeability.
The basis weight of the back sheet is usually about 10 to 50 g / m ² .

In the absorbent article of the present invention, the non-woven sheet serving as the top sheet is in direct contact with the skin of the wearer, promotes blood circulation, is gentle to the skin, and is effective for measures against pressure ulcers and sensitive skin. In addition, the excretion fluid and body fluid of the top sheet permeate through the second sheet quickly and transfer to the absorption layer, and the excretion fluid and body fluid taken in this absorption layer are sealed in it, so that the liquid return prevention property Excellent and cool and soft. Moreover, the absorbent article of the present invention in which a second sheet and an absorbent sheet (installed as necessary) are used between the top sheet and the back sheet is used as an excretory liquid that permeates the top sheet. Since the body fluid is immediately transmitted or absorbed through the second sheet and quickly diffused to reach the absorber sheet, the body fluid permeability, the liquid return preventing property, and the surface dryness are further improved.
Further, when an airlaid nonwoven fabric made of the ultrafine fibers of the present invention is interposed between the absorbent sheet and the backsheet (as (e) a third sheet below), the ultrafine fibers are stored in the absorbent sheet. Prevents urine and other moisture from leaking out of the back sheet.

(E) Third sheet In the absorbent article of the present invention, the airlaid nonwoven fabric of the present invention is preferably used as the (e) third sheet between the (c) absorbent sheet and the (d) backsheet.
When the (e) third sheet made of the air-laid nonwoven fabric of the present invention is interposed between the (c) absorbent sheet and the (d) back sheet, the liquid such as urine stored in the absorbent sheet is made of these ultrafine fibers. (D) It is possible to suppress liquid leakage from the backsheet to the outside as much as possible, and since the nonwoven fabric is made of ultrafine fibers, it has excellent breathability, moisture diffusibility and absorber There is an effect such as moisture transfer to.
(E) The details of the airlaid nonwoven fabric mainly composed of the ultrafine fibers of the present invention used for the third sheet are as described above.

  In addition, the absorbent article of the present invention is applied to the use surface of adult tape-type diapers, in addition to disposable absorbent pads, various absorbent articles such as pants-type diapers themselves, tape-type diapers, obstetric pads, etc. Needless to say, it can be applied to the above.

Moreover, the nonwoven fabric of this invention, such as the above absorbent articles, can be integrally manufactured using the airlaid method.
In this case, the method for producing the nonwoven fabric of the present invention by the airlaid method is, for example, sequentially laminating a top sheet, a second sheet, an absorbent sheet, and, if necessary, a third sheet on the screen of the airlaid apparatus, Each sheet is heat-fixed through the heat-bonding synthetic fibers used in these sheets in the oven, and the resulting non-woven fabric and back sheet are integrated through a thermal calendering process using an adhesive or airlaid method. May be.
Further, by reversing the sheets to be laminated, as a method for producing the nonwoven fabric of the present invention by the airlaid method, for example, on the screen of the airlaid device, a third sheet, an absorbent sheet, a second sheet, and a top sheet are sequentially laminated, Next, each sheet is heat-fixed via heat-adhesive synthetic fibers used in these sheets in a heat oven, and the third sheet side and back sheet of the resulting nonwoven fabric are integrated via an adhesive or the like. May be.

<Absorbent sheet for food>
The nonwoven fabric of the present invention is also useful as a food absorbent sheet that is laid on a fish food tray or the like and supplements the fish drip.
The absorbent sheet for food of the present invention may use the above-mentioned airlaid nonwoven fabric (one layer or two or more layers) as it is, but preferably the following porous film (pores) on the surface of this airlaid nonwoven fabric. Perforated film).

Perforated film (perforated film);
The porous film (perforated film) used in the absorbent sheet for food of the present invention is porous so that the drip of fish meat can permeate to the airlaid nonwoven fabric side as a base material, and titanium dioxide is contained in this film. In order to conceal the color of the drip.
Examples of the material for the porous film (perforated film) include polyolefins, polyamides, polyesters, vinyl chloride resins, and the like, and polyolefins are preferable.

Polyolefin film:
As the polymer constituting the polyolefin film, polyolefin resins such as polypropylene and polyethylene are preferable from the viewpoint of practicality such as water resistance, moldability, and price. Additives such as a deodorant, an antibacterial agent, a colorant, and a hydrophilic agent may be blended in the polyolefin resin.
The thickness of the polyolefin film is 0.05 to 0.5 mm, preferably 0.1 to 0.2 mm. If it is less than 0.05 mm, it is too thin and it is difficult to provide different openings on the front and back surfaces, and food is likely to come into direct contact with the liquid absorbed by the absorber, which is unsanitary. Moreover, if it is too thin, it is too soft and the handleability deteriorates. On the other hand, when it exceeds 0.5 mm, the liquid permeation rate is slow because of being too thick, and the liquid absorption performance is adversely affected.

In addition, a large number of minute holes are formed in the polyolefin film. This hole can be appropriately drilled by means such as a mechanical needle method, a hot needle method, a hot air blowing method from a fine hole, etc., and can be arbitrarily set according to the required hole size and hole diameter difference. You can choose.
Here, the shape of the hole may be any of a circle, an ellipse, a quadrangle (rectangle, regular square), and a triangle.
In addition, the postscript opening diameter in this invention shall represent with the average value of the largest internal dimension among the arbitrary internal dimensions of a hole, and the minimum internal dimension.
The opening diameter is 0.2 to 2.0 mm, preferably 0.3 to 1.0 mm. When the opening diameter is too small, the liquid absorption performance is deteriorated. On the other hand, when the opening diameter is too large, the concealability is deteriorated. It is not preferable.
Here, the number of holes is 5 to 50 holes / cm ² , preferably 10 to 30 holes / cm ² . If it is less than 5 pieces / cm ² , the drip permeability is poor. On the other hand, if it exceeds 50 pieces / cm ² , the strength of the film becomes weak and the concealing property is also deteriorated.
In addition, the polyolefin-type film used for this invention may be a thing with a different hole diameter if it is a range which satisfy | fills said conditions.

Such a polyolefin film having a large number of minute holes can be processed by, for example, passing an ordinary polyolefin film between a hot needle roll and a receiving roll. The temperature of the hot needle roll is preferably 180 to 350 ° C. The optimum temperature of the hot needle roll needs to be changed depending on the material and processing temperature. For example, when processing a polypropylene film, if it is less than 180 degreeC, a hole-drilling defect and adhesion failure will generate | occur | produce, and if it exceeds 350 degreeC, it will cause troubles, such as being fused by a hot roll. More preferably, it is 220-330 degreeC.
The gap between the hot needle roll and the receiving roll is preferably 0.1 to 2 mm. If this distance is less than 0.1 mm, the bulk is crushed and the water retention performance is reduced. On the other hand, if it is more than 2 mm, it may cause poor hole formation or poor adhesion. Preferably it is 0.2-1.5 mm.

Absorber;
As an absorber used as the base material of the food absorbent sheet of the present invention, the air-laid nonwoven fabric of the present invention is used, and it may be a single layer or a multilayer of two or more layers.
By using the airlaid nonwoven fabric of the present invention for the absorbent sheet for food, the drip is diffused in the layer of ultrafine fibers, the wetback is reduced, and the effect of suppressing the growth of bacteria due to the drip coming into contact with meat or fish is effective. I can expect.

  In addition, the absorber used as the base material of the absorbent sheet for food of the present invention needs to have an appropriate water absorbency, and the absorbency of water is usually 5 to 30 g / g, preferably 10 to 20 g / g. It is. If it is less than 5 g / g, the absorbability is insufficient. On the other hand, if it exceeds 30 g / g, water cannot be absorbed unless special fibers such as a polymer water-absorbing polymer are used. This absorptivity can be easily adjusted by appropriately changing the ratio of water-absorbing materials such as pulp and rayon constituting the air-laid nonwoven fabric.

The overall basis weight of the above absorber (including single-layer products, two-layer products, and three-layer products) is usually 20 to 200 g / m ² , preferably 40 to 150 g / m ² . When the amount is less than 20 g / m ² , the amount of water to be retained is insufficient. On the other hand, when the amount exceeds 200 g / m ² , the amount of water to be retained is excessive as a food absorbent sheet.
It should be noted that forming the ultrafine fiber nonwoven fabric including at least one layer of the airlaid nonwoven fabric containing the ultrafine fiber of the present invention in the above-mentioned absorbent body diffuses the drip in the ultrafine fiber layer, reduces wetback, and drip it into meat or fish. It can be expected to be effective in suppressing the growth of bacteria due to contact with the bacterium.

<Laminated integration of porous film and absorbent body (nonwoven fabric)>
The absorbent sheet for food of the present invention is one in which the above porous film is laminated and integrated into a two-layer structure by laminating the absorbent film made of the air-laid nonwoven fabric (ultrafine fiber nonwoven fabric) of the present invention. In order to integrate them, a known method such as a method using hot melt, hot-pressure embossing, or heat-adhesive resin powder can be applied. In order not to impede the performance of the absorber, the hot melt method is preferable. In this case, the hot-melt resin can be selected from polyolefin, polyvinyl acetate, synthetic rubber, urethane, and the like. The application amount of the adhesive is preferably 1 to 20 g / m ² , more preferably ² to 15 g / m ² .

  The food-use absorbent sheet of the present invention thus obtained is excellent not only in strength at the time of drying but also at the time of wetness only by point bonding with heat bonding or hot melt adhesive. Yes. Also, the water absorption is good. Furthermore, since the absorbent sheet for food of the present invention does not use so-called chemical binders such as aqueous emulsions and suspensions, there are no residual emulsifiers, residual monomers, trace formalin due to crosslinking, etc., and there are no safety and hygiene problems. .

Hereinafter, the present invention will be described more specifically with reference to examples.
In the examples, various evaluations were measured as follows.

<Liquid return (wet back), diffusion length test method>
1. Samples Samples shown in Examples 1 to 13 and Comparative Examples 1 to 5 were manufactured on the assumption of absorbent articles (orimono sheets) and used as test samples.
2. Test Method (1) A cylinder (made of plastic having an inner diameter of 20 mmφ, an outer diameter of 55 mmφ, a height of 80 mm, and a weight of 160 g) is placed on the sample.
The method of stacking the samples did not use an adhesive, and a plurality of sheets were stacked with circular stainless steel having an inner diameter of 117 mm, an outer diameter of 210 mm, and a weight of 3,232 g, with a hollow center.
(2) In the center of the cylinder, physiological saline (salt 0.9%, colored blue with a coloring agent brilliant blue 0.05%) is gently poured into 3 cc for 10 seconds.
(3) After 5 minutes have passed, the cylindrical and circular stainless steel are removed, and three filter papers (Advantech Toyo Co., Ltd., circular qualitative filter paper No.2 diameter 90 mm) are placed on the sample. A circular plastic plate (90 mmφ, 73 g) and an iron load (80 mmφ, 500 g) are placed thereon.
(4) Remove the circular plastic plate, iron load and filter paper after 1 minute.
(5) The weight of the filter paper is measured, and the difference between the weights before and after the test is defined as the wetback amount (g).
(6) The top sheet is removed, and the diffusion length (mm) of the physiological saline on the long diffusion surface on the front or back surface of the second sheet or the third sheet is measured with vertical and horizontal, and the average value is obtained.
3. Display of data Each sample was tested three times and expressed as an average value.

Although an Example and a comparative example are described below, the raw material described in it is shown below.
<Thermal bond non-woven fabric A>
Thermal bond method is used to heat the thermoadhesive conjugate fiber (made by Teijin Ltd., product name TJ04CE, 2.2 dt × 51 mm) made of sheath PE (polyethylene) / core PET (polyethylene terephthalate) to 16 g / m ^2. Nonwoven fabric produced by heating at 140 ° C in an oven to cause interfiber bonding

<Airlaid non-woven fabric B>
Thermally-adhesive conjugate fiber (made by Teijin Ltd., product name TJ04V4, 1.7 dt × 3 mm) 50% by weight with a PET core and PE sheath, and 50% by weight of pulverized pulp (Weyerhaeuser, NF405) A non-woven fabric produced by mixing and heating with an airlaid method at 147 ° C. in an airlaid method to 45 g / m ² to form an interfiber bond.

<Moisture permeable film C>
20 g / m ² moisture-permeable film manufactured by the T-die method, which is made of polyethylene resin containing inorganic filler and polyethylene resin.

Example 1
<Thermal bond method nonwoven fabric A> was used for the top sheet.
Under this, a second sheet and a third sheet are combined and integrated, the upper layer is the composition of the above-mentioned <laid array nonwoven fabric B>, the lower layer is a microfiber with a core of PP and a sheath of PE (made by Ube Eximo Co., Ltd., product name) ; Earimo QCE-K, 7.5g / ^{m 2} at 0.2dt × 3mm 100% by weight, i.e. so that a total of 52.5 g / ^{m 2,} and the upper layer / lower layer at the same time non-woven fabric without the use of heat calendar airlaid method Things were placed (referred to as <Airlaid Nonwoven Fabric D>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the result was that the amount of wetback was small, i.e., it was difficult to reverse, as compared with Comparative Example 1, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.
Further, by integrating the second sheet and the third sheet, the wet back amount was small as compared with Example 4 due to moisture diffusibility, that is, it was difficult to reverse.

Example 2
As the top sheet, <thermal bond method non-woven fabric A> was used.
Under this, a second sheet and a third sheet are combined and integrated, the upper layer is the composition of the above-mentioned <laid array nonwoven fabric B>, the lower layer is a microfiber with a core of PP and a sheath of PE (made by Ube Eximo Co., Ltd., product name) An airmoly QCE-K, 0.2dt × 3 mm, 15 g / m ² at 100% by weight, and a total of 60 g / m ² , which was formed into a non-woven fabric simultaneously by using the airlaid method without using a thermal calendar. (<Airlaid non-woven fabric E>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the result was that the amount of wetback was small, i.e., it was difficult to return to Comparative Example 2 due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.
Furthermore, by integrating the second sheet and the third sheet, the wet back amount was small as compared with Example 5 due to moisture diffusibility, that is, it was difficult to reverse.

Example 3
As the top sheet, <thermal bond method non-woven fabric A> was used.
Under this, a second sheet and a third sheet are combined and integrated, the upper layer is the composition of the above-mentioned <laid array nonwoven fabric B>, the lower layer is a microfiber with a core of PP and a sheath of PE (made by Ube Eximo Co., Ltd., product name) An airmoly QCE-K, 0.2 dt × 3 mm, 30 g / m ² at 100% by weight, and a total of 75 g / m ² , which was made into a non-woven fabric simultaneously by using an airlaid method without using a thermal calendar. (<Airlaid non-woven fabric F>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the result was that the amount of wetback was small, i.e., it was difficult to reverse, as compared with Comparative Example 3, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.
Furthermore, by integrating the second sheet and the third sheet, the wet back amount was small with respect to Example 6 due to moisture diffusibility, that is, it was difficult to reverse.

Example 4
As the top sheet, <thermal bond method non-woven fabric A> was used.
Below this, <Airlaid Nonwoven Fabric B> was placed as a second sheet.
Furthermore, as a third sheet for the lower layer, the ultra-fine fiber whose core is PP and whose sheath is PE (Ube Eximo Co., Ltd., product name: Airimo QCE-K, 0.2dt × 3mm, 7.5 wt / m ² at 100% by weight) The one produced without using the thermal calendar by the airlaid method was placed (referred to as <airlaid method nonwoven fabric G>).
That is, unlike Examples 1 to 3, the upper layer (second sheet) / lower layer (third sheet) are separately made into non-woven fabrics.
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the results showed that the amount of wetback was small, i.e., it was difficult to return to Comparative Examples 1 and 4 due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.

Example 5
As the top sheet, <thermal bond method non-woven fabric A> was used.
Below this, <Airlaid Nonwoven Fabric B> was placed as a second sheet.
Furthermore, as a third sheet in the lower layer, the ultra-fine fiber whose core is PP and whose sheath is PE (product of Ube Eximo Co., Ltd., product name; Airimo QCE-K, 0.2dt × 3mm is 15 g / m ² at 100% by weight) The one produced without using a heat calender by the airlaid method was placed (referred to as <airlaid method non-woven fabric H>).
That is, unlike Examples 1 to 3, the upper layer (second sheet) / lower layer (third sheet) are separately made into non-woven fabrics.
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the results showed that the amount of wetback was small with respect to Comparative Examples 2 and 4, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer, that is, they were difficult to reverse.

Example 6
As the top sheet, <thermal bond method non-woven fabric A> was used.
Below this, <Airlaid Nonwoven Fabric B> was placed as a second sheet.
Furthermore, as a third sheet for the lower layer, the lower layer is 30 g / m ² with 100% by weight of ultrafine fiber (product of Ube Eximo Co., Ltd., product name: Airimo QCE-K, 0.2dt × 3 mm) whose core is PP and whose sheath is PE. The one produced without using a thermal calendar by the airlaid method was arranged. (<Airlaid non-woven fabric I>)
An electron micrograph of the surface state of the <airlaid method nonwoven fabric I> is shown in FIG.
That is, unlike Examples 1 to 3, the upper layer (second sheet) / lower layer (third sheet) are separately made into non-woven fabrics.
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the results showed that the amount of wetback was small, i.e., it was difficult to return to Comparative Examples 3 and 4 due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.

Example 7
As the top sheet, <thermal bond method non-woven fabric A> was used.
Below this, <Airlaid Nonwoven Fabric I> was placed as a second sheet.
Furthermore, <airlaid method nonwoven fabric B> was disposed as a third sheet in the lower layer.
That is, from Example 6, the second sheet and the third sheet are reversed.
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the result was that the amount of wetback was small, that is, the comparative example 3 was difficult to reverse, due to the effect of drawing water in the ultrafine fiber layer.

Example 8
As the top sheet, <thermal bond method non-woven fabric A> was used.
Below this, <Airlaid Nonwoven Fabric I> was placed as a composite of the second sheet and the third sheet.
As shown in Table 1, the result was that the amount of wetback was small, i.e., it was difficult to return to Comparative Example 5 due to the effect of drawing water in the ultrafine fiber layer.

Example 9
As the top sheet, <thermal bond method non-woven fabric A> was used.
Below this, as a second sheet, a composite fiber having a core of PP and a sheath of PE (manufactured by JNC Co., Ltd., product name: ES005, 11dt × 5 mm, 100% by weight, 30 g / m ² ) is calendered by the airlaid method. The one manufactured without using the material was placed (referred to as <Airlaid Nonwoven Fabric P>).
Furthermore, <airlaid method nonwoven fabric F> was disposed as a third sheet in the lower layer.
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the result was that the amount of wetback was small, i.e., it was difficult to reverse, as compared with Comparative Example 3, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.
Furthermore, by arranging the second sheet <airlaid method nonwoven fabric P> as compared with Example 3, the wetback amount was smaller than that of Example 3, that is, it was difficult to reverse.

Example 10
As the top sheet, <thermal bond method non-woven fabric A> was used.
Under this, a second sheet and a third sheet are combined and integrated, the upper layer is the composition of the above-mentioned <laid array nonwoven fabric B>, the lower layer is a microfiber with a core of PP and a sheath of PE (made by Ube Eximo Co., Ltd., product name) Airimo QCE-K 0.2dt × 3mm) and PP single ultra-fine fiber (Ube Eximo Co., Ltd., product name Airimo QCP-K 0.2dt × 3mm) are blended at a ratio of 50/50 to 15g / m ² , that is, total The upper layer / lower layer were simultaneously made into a non-woven fabric without using a thermal calendar by the airlaid method so as to be 60 g / m ² . (<Airlaid non-woven fabric N>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the result was that the amount of wetback was small, i.e., it was difficult to return to Comparative Example 2 due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.

Example 11
As the top sheet, <thermal bond method non-woven fabric A> was used.
Under this, a second sheet and a third sheet are combined and integrated. As a result, a superfine fiber (made by Ube Eximo Co., Ltd., product name Airimo QCE-K 0.2dt × 3mm) and pulverized pulp (Weyerhaeuser) NF405) manufactured by the company was blended at a ratio of 50/50, and a non-woven fabric was arranged by the airlaid method without using a heat calender so that the total amount was 30 g / m ² . (<Airlaid non-woven fabric Q>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the result was that the amount of wetback was small, i.e., it was difficult to reverse, as compared with Comparative Example 5, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.

Example 12
As the top sheet, <thermal bond method non-woven fabric A> was used.
Below this, a second sheet and a third sheet are combined and integrated, and the core is made of PP and the sheath is made of PE (Ube Eximo Co., Ltd., product name Airimo QCE-K 0.2dt × 3mm) and the core is PET. Thermal calendering with heat-adhesive conjugate fiber (made by Teijin Ltd., product name TJ04V4, 1.7 dt x 3 mm) with a sheath of PE at a ratio of 50/50 to a total of 30 g / m ² What was made into the nonwoven fabric without using was arranged. (<Airlaid non-woven fabric R>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the result was that the amount of wetback was small, i.e., it was difficult to reverse, as compared with Comparative Example 5, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.

Example 13
As the top sheet, <thermal bond method non-woven fabric A> was used.
Under this, the second sheet and the third sheet are combined and integrated, and the core is PP and the sheath is PE. Ultrafine fiber (product name Airimo QCE-K 0.2dt × 3mm) and PP single Ultrafine fibers (manufactured by Ube Eximo Co., Ltd., product name Airimo QCP-K 0.2dt × 3mm) are blended at a ratio of 50/50 to make a total of 30 g / m ² , making a non-woven fabric without using a thermal calendar by the airlaid method Arranged what was done. (<Airlaid non-woven fabric S>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the result was that the amount of wetback was small, i.e., it was difficult to reverse, as compared with Comparative Example 5, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.

Comparative Example 1
As the top sheet, <thermal bond method non-woven fabric A> was used.
Under this, as a composite of a second sheet and a third sheet, the upper layer is the composition of the above-mentioned <airlaid method non-woven fabric B>, the lower layer is a thermo-adhesive conjugate fiber with PET as the core and PE as the sheath (manufactured by Teijin Limited) ; TJ04V4,1.7dt × 3mm) and 7.5 g / ^{m 2} at 100% by weight, so that a total of 52.5 g / ^{m 2,} was placed those made without the use of heat calendar airlaid method. (<Airlaid non-woven fabric J>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the ultrafine fiber was not used for Example 1, the liquid diffusibility was poor, and the wetback amount was large.

Comparative Example 2
As the top sheet, <thermal bond method non-woven fabric A> was used.
Under this, as a composite of a second sheet and a third sheet, the upper layer is a composition of the above-mentioned <airlaid method nonwoven fabric B>, the lower layer is a heat-adhesive conjugate fiber having a PET core and PE sheath (made by Teijin Limited, product name) TJ04V4) 1.7 dt × 3 mm) was 100 g% and 15 g / m ² , that is, a total of 60 g / m ² was produced without using a heat calender. (<Airlaid non-woven fabric K>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the ultrafine fiber was not used for Example 2, the liquid diffusibility was poor, and the wetback amount was large.

Comparative Example 3
As the top sheet, <thermal bond method non-woven fabric A> was used.
Under this, as a composite of a second sheet and a third sheet, the upper layer is a composition of the above-mentioned <airlaid method nonwoven fabric B>, the lower layer is a heat-adhesive conjugate fiber having a PET core and PE sheath (made by Teijin Limited, product name) TJ04V4) 1.7 dt × 3 mm) was arranged at 100% by weight so as to be 30 g / m ² , that is, 75 g / m ^{2 in} total. (<Airlaid non-woven fabric L>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the results were that no ultrafine fibers were used in Example 3, the liquid diffusibility was poor, and the wetback amount was large.

Comparative Example 4
As the top sheet, <thermal bond method non-woven fabric A> was used.
Below this, <Airlaid Nonwoven Fabric B> was placed as a composite of the second sheet and the third sheet.
<Moisture permeable film C> was disposed in the lowermost layer.
As a result, as shown in Table 1, the ultrafine fibers were not used for Examples 4 to 6, and the wetback amount was large.

Comparative Example 5
As the top sheet, <thermal bond method non-woven fabric A> was used.
Under this, as a composite of a second sheet and a third sheet, 30 g of heat-adhesive conjugate fiber (Teijin Limited, product name TJ04V4) 1.7 dt × 3 mm) whose core is PET and whose sheath is PE is 100% by weight. / M ² was prepared by using the airlaid method without using a thermal calendar. (<Airlaid non-woven fabric O>)
<Moisture permeable film C> was disposed in the lowermost layer.
As shown in Table 1, the results showed that the ultrafine fibers were not used for Example 8, and the wetback amount was large.
As described above, Table 1 shows the results of the absorbent article (carriage sheet).

Next, the following porous film and said nonwoven fabric were combined, and evaluation as an absorbent sheet for foodstuffs was implemented.
Hereinafter, the present invention will be described more specifically with reference to examples.
In the examples, various evaluations were measured as follows.

<Liquid return (wet back), diffusion length test method>
1. Samples Samples shown in Examples 14 to 16 and Comparative Examples 6 to 8 were manufactured assuming food absorbing sheets, and used as test samples.
2. Test Method (1) A cylinder (made of plastic having an inner diameter of 20 mmφ, an outer diameter of 55 mmφ, a height of 80 mm, and a weight of 160 g) is placed on the sample.
(2) In the center of the cylinder, physiological saline (salt 0.9%, colored blue with a coloring agent brilliant blue 0.05%) is gently poured into 3 cc for 10 seconds.
(3) After 5 minutes have passed, the cylinder is removed, and three filter papers (Advantech Toyo Co., Ltd., circular qualitative filter paper No.2 diameter 90 mm) are placed on the sample, and a circular plastic plate ( 90 mmφ, 73 g) and an iron load (80 mmφ, 500 g) are placed thereon.
(4) Remove the circular plastic plate, iron load and filter paper after 1 minute.
(5) The weight of the filter paper is measured, and the difference between the weights before and after the test is defined as the wetback amount (g).
(6) The physiological saline diffusion length (mm) in the absorbent body of the absorbent sheet for food is measured with a vertical and horizontal axis, and the average value is obtained.
3. Display of data Each sample was tested three times and expressed as an average value.

Although an Example and a comparative example are described below, the raw material described in it is shown below.
<Surface material>
A polypropylene film containing titanium dioxide and calcium carbonate having a thickness of 0.12 mm was used. A circular hole having an opening diameter of 0.8 mm and a number of holes of 16 / cm ² was formed in this film by a hot needle method (a taper needle was used to pierce from the film surface). (Referred to as <porous film M>)
<Integration of surface material and absorber>
A polyolefin-based hot-melt adhesive (product name: TN-715) manufactured by Matsumura Oil Research Co., Ltd. was melted at 220 ° C. and sprayed from a number of nozzles onto the absorber together with compressed air. The application amount was 2 g / m ² . Immediately, the surface material and the absorbent body were overlapped and integrated to prepare an absorbent sheet that was a raw fabric, and then the main body was cut into a vertical 16 cm × horizontal 16 cm from the original fabric to prepare an absorbent sheet for food.

Example 14
As the surface material, the above-mentioned <porous film M> is used, and the above <airlaid method nonwoven fabric D> is arranged as an absorber under this, and the surface material and the absorber are integrated with the polyolefin-based hot melt adhesive as described above. An absorbent sheet for food was prepared.
As shown in Table 2, the result was that the amount of wetback was small, i.e., it was difficult to reverse, in comparison with Comparative Example 6, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.

Example 15
The surface material uses the above-mentioned <porous film M>, and the above-mentioned <airlaid method nonwoven fabric E> is arranged as an absorber under this, and the surface material and the absorber are integrated with the polyolefin-based hot melt adhesive as described above. An absorbent sheet for food was prepared.
As shown in Table 2, the result was that the amount of wetback was small, i.e., it was difficult to reverse, in comparison with Comparative Example 7, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.

Example 16
The surface material uses the above <porous film M>, and the above <airlaid method non-woven fabric F> is arranged as an absorber under this, and the surface material and the absorber are integrated with the polyolefin-based hot melt adhesive as described above. An absorbent sheet for food was prepared.
As shown in Table 2, the result was that the amount of wetback was small, i.e., it was difficult to reverse, in comparison with Comparative Example 8, due to the water drawing effect and moisture diffusibility of the ultrafine fiber layer.

Comparative Example 6
The surface material uses the above-mentioned <porous film M>, the above <airlaid method nonwoven fabric J> is disposed as an absorber under this, and the surface material and the absorber are integrated with the polyolefin-based hot melt adhesive as described above. An absorbent sheet for food was prepared.
As shown in Table 2, the result was that no ultrafine fibers were used in Example 14, the liquid diffusibility was poor, and the wetback amount was large.

Comparative Example 7
The surface material uses the above <porous film M>, the above <airlaid method non-woven fabric K> is disposed as an absorber under this, and the surface material and the absorber are integrated with the polyolefin-based hot melt adhesive as described above. An absorbent sheet for food was prepared.
As shown in Table 2, the results were that no ultrafine fibers were used in Example 15, the liquid diffusibility was poor, and the wetback amount was large.

Comparative Example 8
As the surface material, the above-mentioned <porous film M> is used, and the <airlaid method nonwoven fabric L> is disposed as an absorber under this, and the surface material and the absorber are integrated with the polyolefin-based hot melt adhesive as described above. An absorbent sheet for food was prepared.
As shown in Table 2, the result was that no ultrafine fibers were used in Example 16, the liquid diffusibility was poor, and the wetback amount was large.
Table 2 shows the results of the food absorbent sheet.

  The extra-fine fiber nonwoven fabric sheet of the present invention is used as a sheet of absorbent articles in particular, a diffusion sheet for light incontinence, an adult diaper, a dwarf diaper, a food absorbent sheet, a fragrance volatile material, a pet use It is also useful as a sheet, wiper, filter, etc.

Claims (12)

Single fiber fineness of 0.05 to 0.5 dtex, fiber length of 2 to 15 mm, ultrafine fiber of 50 to 100% by weight, other fiber or pulp of 50 to 0% by weight, basis weight of 3 to 50 g / m ² An ultrafine fiber nonwoven fabric comprising at least one airlaid nonwoven fabric and having a single layer or multiple layers.   The ultrafine fiber nonwoven fabric according to claim 1, wherein another nonwoven fabric containing an airlaid nonwoven fabric is laminated on at least the upper layer and / or the lower layer of the airlaid nonwoven fabric according to claim 1.   The ultrafine fiber nonwoven fabric according to claim 1 or 2, which has a multilayer structure and each layer is integrated by an airlaid method.   The ultrafine fiber nonwoven fabric according to any one of claims 1 to 3, wherein the ultrafine fiber is a thermoadhesive conjugate fiber.   The ultrafine fiber is composed of at least one fiber-forming thermoplastic resin selected from the group consisting of polyolefin resin, polyester resin, and polyamide resin, and the melting point of the core component resin is higher than the melting point of the sheath component resin. The ultrafine fiber nonwoven fabric according to any one of claims 1 to 4, which is a core-sheath type thermoadhesive conjugate fiber.   The heat-adhesive conjugate fiber is a core-sheath type conjugate fiber using a polypropylene polymer for the core and a polyolefin polymer having a melting point lower than that of the polypropylene polymer for the sheath, and the single yarn fineness is 0.1 to 0 The ultrafine fiber nonwoven fabric according to claim 5, which is .3 dtex.   The ultrafine fiber nonwoven fabric according to any one of claims 1 to 6, wherein the airlaid nonwoven fabric is embossed and punched.   An absorbent article using the ultrafine fiber nonwoven fabric according to any one of claims 1 to 7. The absorbent article according to claim 8, wherein the following (a) to (d) are sequentially laminated.
(A) A top sheet made of a nonwoven fabric having a basis weight of 10 to 30 g / m ² by a thermal bond nonwoven fabric or an airlaid nonwoven fabric made of fibers having a single yarn fineness of 1 to 3 dtex.
(B) A second sheet comprising 50 to 100% by weight of fibers having a single yarn fineness of 2 to 20 dtex, and a nonwoven fabric having a basis weight of 10 to 60 g / m ² by a thermal bond nonwoven fabric or an airlaid nonwoven fabric.
(C) The ultrafine fiber nonwoven fabric according to any one of claims 1 to 7.
(D) A back sheet made of a film.   The absorption sheet for foodstuffs using the ultra-fine fiber nonwoven fabric in any one of Claims 1-7.   The food absorbent sheet according to claim 10, wherein the ultrafine fiber nonwoven fabric according to any one of claims 1 to 7 is laminated on a porous film. A wiper, a face mask, a fragrance volatile material, a pet sheet, or a filter using the ultrafine fiber nonwoven fabric according to any one of claims 1 to 7.