CN101410080A - Unfolding type absorbent article and method for manufacturing back sheet for absorbent article - Google Patents

Abstract

The invention aims to improve the breakage of a back sheet when a fastening tape is adhered and then peeled off. The following back sheet (12) was used: when laminating a hydrophobic sheet (12A) and nonwoven fabric sheets (12B, 12C) made of hydrophobic resin, the hydrophobic sheet (12A) and the nonwoven fabric sheets (12B, 12C) are laminated with a hot-melt adhesive interposed therebetween, and then thermocompression bonding is performed to form a back surface sheet (12), wherein the bonding strength between the hydrophobic sheet (12A) and the nonwoven fabric sheets (12B, 12C) is higher than the peeling strength when fastening a hook surface material (Y) to the nonwoven fabric sheets (12B, 12C), and the measured value in the bending test of KES is 0.05-0.50 g-cm²/cm。

Description

Expanded absorbent article and manufacturing method of back sheet for absorbent article

technical field

The present invention relates to a method for producing an unfolded absorbent article and a backsheet for an absorbent article.

Background technique

Conventionally, there are known unfolded disposable diapers that include a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body interposed between the two sheets, and are arranged on the left and right sides of the back portion. The fastening belt on the upper part is fastened to the fastening part arranged on the predetermined position of the abdominal part to be worn.

For the back sheet of such diapers, a hydrophobic sheet has been used alone for many years, but in order to improve the touch and feel during use, it has gradually begun to be laminated on the outer side of the hydrophobic sheet (the side that is on the outside when worn). The back sheet of the non-woven sheet. In addition, the back sheet of this laminated structure is produced by superimposing only the non-woven fabric sheet on the hydrophobic sheet, and in this state, it is sent to a roll such as a hot roll or an embossing roll, and heat-compressed. , so as to produce the back sheet. However, before the two sheets are sent to the roller, due to the coincidence deviation caused by the tension difference between the two sheets or the coincidence deviation caused by the vibration of the equipment, sometimes insufficient embossing or insufficient pressing occurs, so The above-mentioned problems can be improved by pre-bonding the two sheets with a hot-melt adhesive before sending them to the roll.

On the other hand, in such a disposable diaper, a surface buckle mechanism is generally used as a fastening mechanism, in which the hook surface material of the surface buckle is used to form all or a part of the fastening belt, and, in the middle of the abdomen, At a predetermined position, the loop material is bonded in the width direction to form a joint, and the above-mentioned hook material is crimped and joined to the loop material as the joint for fastening.

Moreover, in recent years, diapers in which joints are formed on the back sheet itself have been supplied on the market, and such diapers have adopted a surface fastening mechanism called a so-called "non-target belt", in which a nonwoven fabric sheet on the outer surface side is used. The above-mentioned back sheet is constituted, and in this case, the joint portion can be formed on the back sheet itself by embossing or the like in particular on the ventral middle portion of the back sheet in the width direction.

Patent Document 1: Japanese Patent Application Laid-Open No. H10-109371

Patent Document 2: Japanese Patent Application Laid-Open No. 7-285187

Patent Document 3: Japanese Patent Application Laid-Open No. 9-253130

However, in a conventional diaper without a target tape, delamination between the hydrophobic sheet and the non-woven fabric sheet constituting the back sheet or damage to the non-woven fabric sheet may occur after the fastening tape is adhered and peeled off. a lot of. Also, in order to improve the situation, attempts have been made to increase the amount of hot melt adhesive used to bond the two, or to increase the amount of embossing to increase the bond strength, but if these means are used alone to completely prevent the layer If the film is peeled off, no matter which method is used, the back sheet will become hard, the touch will be poor, and the feeling during use will be very poor.

On the other hand, if it is desired to make a simple compromise between increasing the amount of hot melt adhesive and increasing embossing, during manufacture, after bonding with hot melt adhesive, when it is provided to the embossing roller, there will also be problems. The manufacturing problem is that the hot melt adhesive is melted by the heat of the embossing roll, overflows from the surface of the nonwoven fabric, and the two sheets are stuck on the embossing roll, causing a problem in operation.

Contents of the invention

Therefore, the main object of the present invention is to prevent damage to the back sheet when the fastening tape in the so-called non-target tape disposable diaper is peeled off after adhesion without impairing touch and softness. Another problem is to prevent the back sheet from adhering to the embossing roll due to the hot-melt adhesive during production of the back sheet, and to prevent operational problems and deterioration of the touch of the back sheet. In addition, another subject is that it is easy to fasten to a reliable position without repeated operations by the fastener, and it is possible to prevent leakage from the wearer.

The present invention which solves the above-mentioned problems and its operations and effects are as follows.

<Invention described in claim 1>

An unfolded absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body interposed between the two sheets, and on the left and right sides of either the back side or the abdomen side The part is provided with a fastening belt, and a part or all of the fastening belt is formed by the hook surface material of the surface buckle, and the hook surface material is joined to the junction between the left and right side parts of the ventral part or the back part. For wearing, the unfolded absorbent article is characterized in that the back sheet is made of a hydrophobic sheet made of a hydrophobic resin and a non-woven fabric sheet constituting the outer surface of the above-mentioned article. It is formed by laminating the mixture and then performing thermocompression bonding. The adhesive strength of the above-mentioned hydrophobic sheet and the non-woven fabric sheet is higher than the peel strength when the above-mentioned hook surface material is fastened on the non-woven fabric sheet, and the KES The measured value in the bending test is 0.05 to 0.50 g·cm ² /cm.

(Effect)

At the junction where the fastening tape is joined, peeling after adhesion (detachment after adhesion) will also exert a peeling force on the laminated back sheet. Therefore, if the adhesion between the hydrophobic sheet and the non-woven sheet If the strength is less than the peel strength when the hook material is fastened on the non-woven fabric sheet and then peeled off, interlayer peeling or damage to the non-woven fabric sheet will occur. However, in the present invention, the gap between the hydrophobic sheet and the non-woven fabric sheet The adhesive strength is higher than the peeling strength when the hook surface material is fastened on the non-woven fabric sheet and then peeled off, so no damage will occur.

On the other hand, in the unfolded absorbent article of the present invention, the measured value in the KES bending test of the back sheet is 0.05 to 0.50 g·cm ² /cm, so the product has excellent touch and softness, and the product has stiffness , There will be no problems such as shrinkage when wearing.

In addition, when the peel strength when fastening the hook surface material to the nonwoven fabric sheet is less than 200 gf, problems such as detachment of the fastening tape may occur when the product is worn. On the contrary, if it is too high, if the peel strength when fastening the hook surface material to the nonwoven fabric sheet exceeds 1000gf, the force required to detach after attachment is large, and the product is very difficult to use.

Accordingly, the adhesive strength between the hydrophobic sheet and the nonwoven fabric sheet is preferably 200 to 1000 gf/25 mm.

<Invention described in claim 2>

The unfolded absorbent article according to claim 1, wherein the amount of the hot-melt adhesive used between the hydrophobic sheet and the nonwoven fabric sheet is 0.5 to 30.0 g/m ² .

(Effect)

The amount of the hot-melt adhesive used between the sheets is preferably 0.5-30.0 g/m ² . If it is the usage-amount within this range, solidification by heat fusion can be prevented, and the absorbent article which has the back sheet for absorbent articles excellent in touch can be obtained. In addition, when embossing is applied to the production of the back sheet, it is possible to reliably prevent the hot melt adhesive from overflowing or the back sheet to be entangled with the embossing roll, thereby obtaining a disposable diaper that is easy to manufacture.

<Invention described in claim 3>

The unfolded absorbent article according to claim 1 or 2, wherein the nonwoven fabric sheet is laminated after laminating the hydrophobic sheet and the nonwoven fabric sheet with the hot melt adhesive interposed therebetween. The side is located on the convex roll side of the embossing roll, and they are heat-compressed while embossing.

(Effect)

The hydrophobic sheet is difficult to adhere to the heated embossing roll, and the operational problems of rolling on the embossing roll are significantly reduced. As a result, solidification of the hot melt can be prevented, and an absorbent article having a back sheet for absorbent articles excellent in touch can be obtained.

In addition, since the hot-melt adhesive overflows less from the nonwoven fabric and does not adhere to the embossing roll, a larger amount of hot-melt adhesive can be used than before, thus improving the bond between the two sheets. between the bond strength. In addition, other nonwoven fabric sheets may be interposed between two sheets.

<Invention described in Claim 4>

The unfolded absorbent article according to any one of claims 1 to 3, wherein, before the thermocompression bonding, between the hydrophobic sheet and the nonwoven fabric sheet, a different of other materials.

(Effect)

By interposing other material sheets, it is possible to obtain an absorbent article having a back sheet of a multilayer structure with rich diversity. Thereby, for example, it is possible to form a bulky portion in which another material sheet is partially interposed, and to form an absorbent article having a back sheet of a firm layer structure in which the layers are hardly peeled off.

<Invention described in claim 5>

The unfolded absorbent article according to claim 4, wherein the other material sheet is a nonwoven fabric made of a hydrophobic resin.

(Effect)

As another material sheet, if a nonwoven fabric made of a hydrophobic resin is used, it is possible to form an absorbent article having a back sheet excellent in various aspects such as ensuring flexibility and bulkiness.

<Invention described in claim 6>

The unfolded absorbent article according to claim 4 or 5, wherein the thermocompression bonding is performed only on the joining portion.

(Effect)

When thermocompression bonding is performed, the feel of this portion decreases, but by thermocompression bonding only the joining portion, an absorbent article excellent in feel as a whole can be obtained.

<Invention described in claim 7>

The unfolded absorbent article according to claim 6, wherein the junction part is composed of a pair of left and right junction parts, the junction parts are arranged separately at least at the center of the width direction of the product, and the hook surface material is arranged on the separated part. Engagement is not enough to use.

(Effect)

The junction part of the conventional disposable diaper is designed so that the width may expand from the center part in the width direction of the abdominal middle part toward both sides, but the center part in the width direction is hardly used for joining. Then, by providing the separating portion at the center in the width direction of the joining portion, the range of curing by thermocompression bonding can be minimized, and an absorbent article excellent in touch as a whole can be obtained.

And, the joint portion of existing disposable diaper is designed so that the width expands toward both sides from the central part of the width direction of the central part of the abdomen, so the person who fastens (hereinafter referred to as the fastening person) easily puts a fastening belt Fastening to the central portion, or, across or beyond the central portion, fastening to the other side of the fastening strap, sometimes fastening the fastening strap to such a central portion, etc.

For example, when the wearer is an infant, the fastening may turn against the fastening user's intention, and such fastening may occur when the fastening operation is performed quickly. In addition, when the fastening person is the wearer, usually, the fastening belt is held with one hand and the side flap is fastened with the other. After the two are pulled and joined, at this time, the side wings on the unhandled side are loosened and joined to the vicinity of the central part.

And, in the case of joining the fastening belt on the central part or beyond the central part like this, in most cases, it is necessary to re-fasten the fastening work, and if it is slightly exceeded, if the wearer continues to wear it, Then, along with the movement of the wearer, the displacement increases and leakage may occur.

As in the invention described in this item, the joint part is composed of a pair of left and right joint parts. The above problem occurs. Therefore, the fastening person does not need to re-operate, and it is easy to fasten to a reliable position, and leakage of the wearer can be prevented.

<Invention described in claim 8>

The unfolded absorbent article according to any one of Claims 4 to 7, wherein the other material sheet is arranged only on the joining portion and its periphery.

(Effect)

By thermocompression-bonding the portion bulked with another material sheet, the difference in unevenness of the thermocompression-bonded part increases, and a junction part with excellent engaging force can be formed.

<Invention described in claim 9>

The unfolded absorbent article according to any one of claims 1 to 8, wherein the coating pattern of the hot-melt adhesive is formed by arranging a plurality of continuous coating lines at predetermined intervals in the front-back direction or in the width direction of the article. pattern, the width of the above-mentioned coating line is 0.1-3 mm, and more than 90% of the area of the above-mentioned hydrophobic sheet is coated; or, the coating pattern of the above-mentioned hot-melt adhesive is dot-shaped coating points arranged in scattered In a dot-shaped pattern, the area of the coating dots is 0.05 to 5 mm ² , and 90% or more of the area of the hydrophobic sheet is coated.

(Effect)

As the application pattern of the hot-melt adhesive, as described in this item, a linear or dot pattern is easy to produce, and thus is preferable. Also, uniform coating can be achieved, thereby improving the touch of the product. In particular, in the case of ensuring the water pressure resistance described later, if the total coating area is too small, even if the liquid-blocking property of the nonwoven fabric itself is high, it is easy to cause insufficient liquid-blocking sustainability. If the line width or dot area is too small , no matter how much the total coating area or coating amount is, it will easily lead to insufficient liquid shielding continuity, and if the line width or dot area is too wide, the air permeability will easily deteriorate. Therefore, it is preferably within the range described in this item. In addition, "scattered" includes both regular arrangement and irregular dispersion.

<Invention according to claim 10>

The unfolded absorbent article according to any one of claims 1 to 9, wherein the hydrophobic sheet is a nonwoven fabric made of a hydrophobic resin, the hot-melt adhesive is made of a water-insoluble hot-melt resin, and The water pressure resistance of the said back sheet is 400 mmAq or more at least in the range which interposes the said hot-melt adhesive.

(Effect)

In the non-target tape embodiment of the present invention, the force is concentrated at the junction of the hook surface material in the backsheet as described above, and the backsheet sometimes peels from the hydrophobic sheet due to intralayer or interlayer peeling. When such peeling occurs, the tightened fastening tape becomes loose, or the fastening tape becomes loose, and in this state, leakage is likely to occur from gaps formed around the abdomen or around the legs. The invention described in this item is carried out in view of such a problem. A nonwoven fabric made of a hydrophobic resin is used as a hydrophobic sheet to increase the interlayer strength of the sheets constituting the back sheet. By setting the water pressure resistance to 400 mmAq, Thereby preventing back leakage of liquid. Thereby, the hook element is properly joined to the exterior sheet while maintaining flexibility and air permeability.

<The invention described in Claim 11>

The unfolded absorbent article according to any one of claims 1 to 10, wherein the application amount of the hot-melt adhesive in the joining portion is locally increased compared to other portions.

(Effect)

By locally increasing the amount of coating at the joining position of the joining part, the strength of the joining position of the joining part can be improved.

<The invention described in Claim 12>

The unfolded absorbent article according to claim 10 or 11, wherein the nonwoven fabric used in the hydrophobic sheet is a single-layer nonwoven fabric or a laminated nonwoven fabric having two or more layers, and at least one layer is composed of It is composed of fibers less than 1.2dtex (dtex), and the fiber basis weight is above 15-25g/ ^m2 .

(Effect)

The ultrafine or ultrafine fiber layer described in this item is very preferable for ensuring the above-mentioned water pressure resistance because of its very high liquid-blocking properties. In particular, a laminated nonwoven fabric is very preferable because it has the advantage of being able to protect the low-strength ultrafine fiber layer with another layer.

<The invention described in Claim 13>

A method for producing a backsheet for an absorbent article, for producing the above-mentioned backsheet used in an absorbent article in which an absorbent body is interposed between a liquid-permeable topsheet and a liquid-impermeable backsheet, wherein the backsheet is composed of The hydrophobic sheet made of hydrophobic resin and the non-woven fabric sheet are laminated with a hot-melt adhesive interposed between them, and then the sheets are heat-pressed. The peel strength at 40° C. in the joint test is 0.0 to 5.0 N/25 mm.

(Effect)

By bonding the hydrophobic sheet and the nonwoven fabric sheet together using a hot-melt adhesive having a predetermined peel strength, it is possible to manufacture a back sheet with reduced adhesive spillage from the nonwoven fabric surface and excellent adhesion of each sheet.

<Invention according to claim 14>

According to the method for producing a back sheet for an absorbent article according to claim 13, in the thermocompression bonding, the thermocompression bonding is performed while performing embossing at an embossing pressure of 3 to 20 kgf/cm ² .

(Effect)

When the embossing pressure is 3 to 20 kgf/cm ² , the two sheets are reliably bonded together and the back sheet is formed with particularly excellent touch.

Invention effect

According to the present invention, it is possible to prevent the back sheet from being damaged when the fastening tape in a disposable diaper without a target tape is peeled off after sticking without impairing touch and softness. Furthermore, it is possible to prevent the back sheet from adhering to the embossing roll due to the hot-melt adhesive during production of the back sheet, and to prevent workability problems and deterioration of the touch of the back sheet.

Description of drawings

Fig. 1 is a plan view of the unfolded state of the diaper according to the first embodiment seen from the outer surface side.

Fig. 2 is a plan view of the unfolded state of the diaper according to the second embodiment seen from the outer surface side.

Fig. 3 is a plan view showing a preferred embossing pattern.

Fig. 4 is a plan view showing another preferable embossing pattern.

It is a top view which looked at the unfolded state of the diaper of 3rd Embodiment from the inner surface side.

Fig. 6 is a sectional view taken along line 2-2 in Fig. 5 .

Fig. 7 is a conceptual diagram of a back sheet.

FIG. 8 is a plan view showing various coating patterns.

FIG. 9 is a plan view showing various coating patterns.

Fig. 10 is a plan view showing various coating patterns.

Fig. 11 is a sectional view showing various hook materials.

Fig. 12 is a schematic diagram of a production apparatus for a back sheet.

Explanation of reference signs

X, X1, X2...Natural material sheet, Y, Y1, Y2...Hook material (fastening tape), Z, Z1, Z2...Disposable diaper, 3...Embossing processing device , 3A...Convex embossing roller, 3B...Rubber roller, 5...Coating machine, H...Hot-melt adhesive part, 11...Front sheet, 12...Back sheet, 12A ...hydrophobic sheet, 12B, 12C...nonwoven fabric sheet, S1, S2...reel roll, 13...absorbent body.

Detailed ways

<Embodiment of Expanded Absorbent Article (hereinafter, sometimes simply referred to as Absorbent Article)>

(first embodiment)

Fig. 1 is a developed view showing a fastening type disposable diaper Z of the present invention. This disposable diaper Z has: a liquid-permeable top sheet 11 positioned on the user's skin side; a liquid-impermeable back sheet 12 positioned on the outside of the product that does not allow liquid to permeate substantially; The absorber 13 is preferably hourglass-shaped and has a certain degree of rigidity, and the fastening tapes Y1 and Y2 for fastening are arranged on the left and right sides of the back side. In this form, the fastening belts Y1, Y2 are formed using a hook surface material of a surface fastener, and an engaging portion X for engaging with an exposed portion of the hook surface material is formed on the ventral portion of the outer surface of the back sheet 12. superior.

The back sheet 12 is formed in a substantially square shape wider than the absorber 13, and the nonwoven fabric sheet 12B for exterior is laminated on the outer surface of the hydrophobic sheet 12A made of hydrophobic resin (non-polar resin) to improve skin contact, Bonding is carried out by thermocompression bonding or the like to form the back sheet 12 . As the hydrophobic resin used for the hydrophobic sheet 12A, polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) and other olefin-based, polyester-based, polyamide-based, polyurethane Department of other resins. As the hydrophobic sheet 12A, in addition to the film form, fiber aggregates such as nonwoven fabrics can also be used, that is, the back sheet 12 can be formed by laminating the nonwoven fabric as the hydrophobic sheet 12A and the nonwoven fabric sheet 12B for exterior. Together to form. The thickness and rigidity of the hydrophobic sheet 12A can be appropriately selected in accordance with known standards in consideration of the thickness and rigidity of the nonwoven fabric sheet to be laminated. When a nonwoven fabric is used as the hydrophobic sheet 12A, basically the same material as the nonwoven fabric sheet 12B for exterior packaging described later can be used as the nonwoven fabric, but it does not have to be the same material. If necessary, select the appropriate material independently.

The nonwoven fabric sheet 12B for exterior can use the known nonwoven fabric sheet used on the back sheet 12 of the absorbent article Z, for example, by air-through (air-through), point bonding (pointbond), air Appropriate processing methods such as thread-forming bonding method, spunlace method, spunbonding method, thermal bonding method, meltblown method, needle-punched weaving method, heat shrinking method, etc., are suitable for polyethylene (PE) or Olefin-based fibers such as polypropylene (PP), polyethylene terephthalate (PET), synthetic fibers such as polyester-based, polyamide-based, and polyurethane-based fibers, or mixed fibers such as (PE)/(PET), artificial It is a non-woven fabric obtained by processing a fiber web composed of regenerated fibers such as silk or copper ammonia silk, and natural fibers such as cotton. In addition, among the processing methods, the spunlace method is excellent in flexibility and rich wrinkle properties, and the thermal bonding method is excellent in bulkiness and rich flexibility, and can be appropriately selected according to the purpose. Also, the nonwoven fabric sheet may be a laminated nonwoven fabric sheet, for example, a spunbond nonwoven fabric (S) layer formed by a spunbond method and a meltblown nonwoven fabric formed by a meltblown method into a fiber web may be used. The cloth layer (M) is a nonwoven fabric laminate obtained by appropriately laminating two or more layers as a material.

The fineness of the fibers used for the nonwoven fabric sheet 12B is preferably about 1.8 to 3.0 decitex. The basis weight of the nonwoven fabric sheet 12B is about 10 to 100 g/m ² , more preferably about 15 to 50 g/m ² . When the basis weight of the non-woven fabric sheet is too low, the space for winding the hook surface material cannot be fully maintained, and when the fastening tapes Y1, Y21, Y1, and Y22 are peeled off, the non-woven fabric sheet 12B is damaged; Therefore, the production efficiency of the nonwoven fabric sheet 12B deteriorates, and the fastening tapes Y1 , Y21 , Y1 , and Y22 are conspicuously fastened to parts other than the joining portion X, which is not preferable.

The back sheet 12 is preferably configured to have a water vapor transmission rate of 0.5 to 4.0 g/100 cm ² hr (g/100 cm ² hr). Preferably, the fiber loops and fiber arches on the surface of the exterior nonwoven fabric sheet 12B are relatively dense at locations other than the joint portion, and are not bonded to the hook surface material.

In the range on the ventral side including the joining portion X of the back sheet 12, an intermediate layer nonwoven fabric sheet 12C as another material sheet formed of a nonwoven fabric sheet is further interposed between the sheets 12A and 12B. By interposing the intermediate non-woven fabric sheet 12C, this part becomes bulky, and the pressing feeling when the fastening tapes Y1, Y21, Y1, and Y22 are crimped to the joint parts X1, X2 is excellent, and the interlayer peel strength is excellent. Improvement can prevent delamination of the exterior nonwoven fabric sheet 12B due to peeling of the fastening tapes Y1, Y21, Y1, and Y22 after adhesion. As the intermediate layer nonwoven fabric sheet 12C, basically the same material as that of the exterior nonwoven fabric sheet 12B can be used, but the same material does not have to be used, and an appropriate material can be selected individually as needed. On the intermediate nonwoven fabric sheet 12C, a design or a pattern serving as a position target at the time of fastening is printed by printing or the like, so that it can be visually recognized from the outside through the exterior nonwoven fabric sheet 12B. In addition, the middle nonwoven fabric sheet 12C may be provided in the same size as the exterior nonwoven fabric sheet 12B.

Desirably, the peel strength of hydrophobic sheet 12A and nonwoven fabric sheet 12B at the interposed portion of intermediate nonwoven fabric sheet 12C is 100 to 1500 gf/25 mm, preferably 200 to 1000 gf/25 mm. In addition, peel strength can be measured using the tensile tester (AOUTGRAPHAGS-G100N by Shimadzu Corporation). The measurement method is as follows: make a sample cut into 25mm×130mm, and peel off 5cm along the length direction in advance to form a peeling opening. The measurement was performed by peeling off a length of 30 mm from the peeling port using a tensile tester. As samples, two types of samples whose longitudinal direction is the product longitudinal direction and samples whose longitudinal direction is the product transverse direction were produced, measured respectively, and the obtained values were averaged as measured values.

The back sheet 12 is manufactured by the manufacturing method described later, that is, the hydrophobic sheet 12A and the non-woven fabric sheets 12B, 12C are laminated with a hot-melt adhesive interposed therebetween, and the exterior non-woven fabric sheet 12B side is positioned on the pressing surface. The embossing process is performed on the convex roll side of the embossed roll, and the sheets are laminated and bonded to form the back sheet 12. The hot-melt adhesive peels off at 40°C in the cyclic adhesion test specified in JIS Z 0237. The strength is 0.0~5.0N/25mm.

In the back sheet 12, the KES bending measurement value is preferably 0.05 to 0.50 g·cm ² /cm, more preferably 0.10 to 0.45 g·cm ² /cm, and most preferably 0.20 to 0.40 g·cm ² /cm. When the measured value in the KES bending test is 0.05 g·cm ² /cm or less, the product is too soft, so the stiffness of the product is lost, and problems such as shrinkage occur when worn. On the contrary, if it exceeds 0.50 g·cm ² /cm, the touch and softness of the product will be impaired. In addition, the bending measurement value of KES in the present invention is to use a pure bending tester (manufactured by IPROS: KES-FB-2AOUT-A), and set a sample cut into a length of 200mm and a width of 200mm on the above-mentioned testing machine to obtain The value when the DFE sensitivity is 20 and the curvature range is 0.0 to 0.5 cm ^-1 when bending.

The joining portion X of this embodiment is formed by performing appropriate embossing for forming the joining portion on an appropriate range from the central portion to both sides in the abdominal width direction (abdominal peripheral direction) of the back sheet 12, in other words, the back surface part of the outer surface of sheet 12. For example, the produced back sheet 12 is supplied to an embossing device with the nonwoven fabric sheet side positioned at the side of a convex embossing roll, thereby performing embossing for forming a junction. And a rubber roll on which an embossed embossed pattern for a joining portion is formed, and the rubber roll has flexibility to the extent that the convex portion of the convex embossed roll facing the rubber roll can be press-fitted. It is also possible to use an embossing device provided with a concave embossing roll on which recesses corresponding to the convexities of the convex embossing roll are formed. In addition, the embossed pattern in the embossing roll is provided only on the portion corresponding to the joint portion when the back sheet 12 is produced, and the joint portion X is formed when the back sheet is produced.

Here, when forming the junction X by embossing, the embossing depth and embossing density at this time are set appropriately according to the basis weight of the nonwoven fabric sheet and the structure of the hook surface material. . Here, as the embossing pattern given to the joining portion, a known pattern formed on such a non-target belt type can be used, and it is preferable that the embossing is arranged along the MD (longitudinal) direction or the CD (transverse direction) direction when forming the back sheet. picture of. In this way, usually when a product is produced, it becomes a pattern in which embossing is arranged along the longitudinal direction or the width direction. Furthermore, especially when the CD direction of the back sheet is the product width direction, the embossing pattern is preferably a pattern in which the embossing is along the CD direction when the back sheet is formed or continuously connected. In this case, interlayer detachment due to post-adhesion detachment of the fastening tape and fluffing of the nonwoven fabric sheet are less in particular.

And, especially when the peel strength when fastening the hook surface material to the non-woven fabric sheet is less than 200gf, etc., the belt may fall off when wearing the product, so the joint X is preferably such that the hook surface material is fastened to the nonwoven fabric sheet. The peel strength when on the non-woven fabric sheet exceeds 200gf. In addition, when the peel strength of the hook surface material when fastened to the nonwoven fabric sheet exceeds 1000 gf, the force required for detachment after attachment increases, and the product is very difficult to handle. Therefore, the peeling strength between the nonwoven fabric sheet and the hook surface material in the joining portion X is preferably 100 to 1500 gf/25 mm, preferably 200 to 1000 gf/25 mm. Therefore, in order not to cause interlayer delamination at the above-mentioned junction X, the adhesive strength between the hydrophobic sheet 12A and the nonwoven fabric sheet 12B in the back sheet 12 is set at least in the range of the junction X, and is 100 to 1500 gf. /25mm is preferably within the range of 200 to 1000 gf/25mm, and is a value larger than the peel strength between the nonwoven fabric sheet 12B and the hook surface material in the joining portion X.

The peel strength can be measured using a tensile tester (Aoutgraph AGS-G100N manufactured by Shimadzu Corporation). The measurement method is as follows: make a sample (back sheet) cut into 25mm×130mm, peel off 5cm along the length direction in advance to form a peeling opening, and under the condition of 20°C, the distance between the chucks is 50mm, and the tensile speed is 300mm/min. , and measured by peeling off a length of 30 mm from the above-mentioned peeling port with a tensile tester. As samples, two kinds of samples whose longitudinal direction is the product longitudinal direction and the samples whose longitudinal direction is the product transverse direction were produced, and the values measured respectively were averaged as measured values.

In addition, the junction part X may be formed not by embossing, but by pin insertion processing etc., for example. As a method for forming the joining portion X, a known method can be appropriately employed without departing from the scope of the present invention.

On the other hand, as explained above, the part where the joining part X is formed has a three-layer structure in which the middle layer non-woven fabric sheet is interposed with the back sheet 12, and its strength is high and the amount of adhesive is relatively small compared with other parts. There are many, and the bonding strength of each sheet is high, so even if the fastening tape is repeatedly attached and released, it is difficult to cause damage to the back sheet.

On the other hand, the surface sheet 11 is wider than the absorber 13, extends outward than the side edge 13s of the absorber 13, and is bonded to the back sheet 12 at the periphery of the absorber 13 by hot-melt adhesive or the like. Together. The surface sheet 11 can be used as long as the liquid permeability can be ensured in addition to various nonwoven fabrics such as spunbond nonwoven fabric, air-through nonwoven fabric, SMS nonwoven fabric, point bonded nonwoven fabric, etc. A plastic film such as a polyethylene film, or a laminated nonwoven fabric obtained by laminating a plastic film and a nonwoven fabric. In addition, a mesh material obtained by plain weaving yarns of nylon, polyethylene terephthalate, or the like can also be used.

Absorbent body 13 is formed by containing an absorbent polymer in a fiber aggregate composed of aggregated fiber pulp or tow, and covering it with a pulp sheet or the like. Examples of fibers constituting the fiber aggregate (hereinafter simply referred to as fibers constituting tow) include polysaccharides or their derivatives (cellulose, cellulose ester, chitin, chitosan, etc.), synthetic high Molecules (polyethylene, polypropylene, polyamide, polyester, lactamide, polyvinyl acetate, etc.), etc., especially cellulose ester and cellulose.

As superabsorbent polymers, hydrolyzates of carboxymethylcellulose, polyacrylic acid and its salts, acrylate polymer cross-linked products, starch-acrylic acid graft copolymers, and starch-acrylonitrile graft copolymers can be used. , polyoxyethylene cross-linked product, carboxymethyl cellulose cross-linked product, polyethylene oxide, polyacrylamide and other water-swellable polymers partially cross-linked polymers, or the copolymerization of isobutylene and maleic acid is preferably used things etc. In order to suppress the caking property caused by moisture absorption of the product, it is also possible to use a material with an anti-caking agent added. In addition, as a superabsorbent polymer, there are various forms such as powder form, granular form, granular form, pellet form, sol form, suspension form, gel form, film form, and nonwoven form, and these can be used in this article. For use in the invention, it is particularly preferable to adopt a granular form.

In addition, the absorbent article of this invention is not limited to this form. For example, an aspect in which elastic stretchable members such as rubber bands used in disposable diapers and the like are arranged at each position may be employed. An aspect in which a second sheet is provided between the top sheet and the absorber for the purpose of liquid diffusion or the like may also be employed. In addition, the middle non-woven fabric sheet 12C and/or the thermocompression-bonded portion extend to the lateral sides in the product width direction on the flaps on the abdominal side, and the flaps on the sides create a proper waist and are easy to wear, so it is preferable.

(second embodiment)

Fig. 2 is a fastening type disposable diaper Z1 according to a second embodiment. Since the basic structure of this disposable diaper Z is the same as that of 1st Embodiment, the same code|symbol is used for the same part, and description is abbreviate|omitted.

In the second embodiment, a method called a so-called non-target tape is adopted, that is, a part of the outer surface of the back sheet 12 itself is appropriately embossed without attaching a matte material to the back sheet, thereby forming Joints X1, X2. Furthermore, on the back sheet 12, the intermediate nonwoven fabric sheet 12C is arranged between the exterior nonwoven fabric sheet 12B and the water-repellent sheet 12A within the range including the junction portions X1 and X2 formed therein.

The fastening belts Y1 and Y2 arranged on the left and right sides of the back side are made of the hook surface material (not shown) of the surface buckle except for the parts glued to the left and right sides. On the ventral side of the outer surface of the back sheet 12 for joining the hook material, the left side joint X1 for fastening the left fastening tape Y1 and the left side for fastening the right fastening tape Y2 are arranged respectively. Junction X2.

It is characterized in that these left joint X1 and right joint X2 are separated by a predetermined distance in the width direction of the product. In addition, in the illustrated example, a particularly preferable form of the joining portions X1, X2 is a rectangle, but it is not particularly limited thereto. Other shapes are also possible.

The separation distance (the distance of the closest part) L2 between the joint parts X1 and X2 is also related to the length of the fastening belt Y1 and Y2, which is the product width ( Hereinafter, the product width is referred to as 1/2 or more of the width) 5.0 to 500 mm, or 1/2 or more of the product width direction dimension of the hook surface material. If this range is not reached, the separation of the joining parts X1 and X2 will not be visually recognized, or when the fastening operation is performed quickly, the fastening tapes Y1 and Y2 may be wrongly fastened on the center line in the width direction of the product. on the joint opposite the corresponding joint. For example, it is basically impossible to prevent the left fastening tape Y1 from being joined to the right joining portion X2. In addition, as mentioned above, when the middle non-woven fabric sheet 12C and/or the thermocompression portion extends to the side portions in the width direction of the product, an appropriate waist is formed on the side flaps, making it easier to wear, so it is preferable.

On the other hand, although not shown, in the disposable diaper Z1 of this form, a plurality of elastic elastic elastic bands extending in the direction between the fastening belts are arranged, thereby constituting the fastening belts Y1 and Y2 on the back side. scalable between. Therefore, the allowable fastening range of the fastening belts Y1 and Y2 at the time of fastening is expanded, and the allowable fastening range based on the difference in the body shape of the wearer is expanded. In addition, stretching and contraction improves the fit during wearing. It is also possible to adopt a method in which an elastic body sheet or the like is interposed between the front end and the base end of the fastening tapes Y1, Y2 instead of stretching and contracting between the fastening tapes Y1 and Y2 on the back side with a rubber band. The elastic member is arranged, and the hook surface material of the surface buckle is arranged at a position closer to the front end than the interposed elastic member, so that the fastening belts Y1, Y2 themselves are stretched and contracted. Furthermore, by interposing stretchable members such as elastic body sheets between the so-called side flaps and other parts of the adhesive fastening tapes Y1, Y2, the rear fastening tapes Y1, Y2 are configured to be stretchable. With such a configuration, it is also possible to obtain the effects of improving the feeling of closeness and increasing the allowable range of the difference in body shape. In addition, the stretching force of the elastic band or the elastic member can be designed within the range employed in known disposable diapers without any problem.

Here, the hook surface material of the surface buckle constituting a part or all of the fastening tapes Y1, Y2 is constituted by a hook surface material sheet having a hook shape or hook shape which is wound on the non-woven fabric fiber as the joint portion and joined. Hair-like protruding elements (joint protrusions) such as mushroom-shaped puffy heads. The method of manufacturing the fastening tape from the hook material sheet employs a known method. Not particularly limited. In addition, the size and density of the hook-shaped or mushroom-shaped fluff-shaped protrusion-shaped elements can be appropriately selected within the range of appropriate peel strength according to the relationship with the non-woven fabric for exterior.

The suitable peeling strength between the fastening strips Y1, Y2 and the joints X1, X2 is designed to be 100gf-1500gf/25mm, preferably 200gf-1000gf/25mm. If it is less than 100 gf, sufficient bonding cannot be achieved; if it exceeds 1500 gf, the bonding force will be too strong, and fluffing will easily occur at the bonding portion when peeling after adhesion. In addition, in the present invention, in order not to join the hook surface material to the site between the joining parts X1 and X2, the peeling strength is preferably less than 100 gf.

Here, the peel strength can be measured using a tensile tester (AOUTGRAPH AGS-G100N manufactured by Shimadzu Corporation). The method of measuring the peel strength is as follows. Fold the cloth tape with width 50mm×length 100mm in half along the width direction to form a folded cloth tape with width 25mm×length 100mm, and stick fastening tapes Y1 and Y2 firmly on one end of the cloth tape. At this time, the hook surface materials of the fastening tapes Y1 and Y2 are positioned outward from the front ends of the tapes.

On the other hand, on a flat plate made of stainless steel, the joining portions X1 and X2 of the back sheet 12 were used as the upper surface, and were stuck with a double-sided adhesive tape. Also, secure the ends with tape.

Next, after the hook surface materials of the fastening tapes Y1, Y2 are brought into contact with the joint parts X1, X2, a roller with a mass of 2 kg is used to go back and forth on them from the cloth tape side, and the hook surfaces of the fastening tapes Y1, Y2 are brought into contact with each other. The material and joints X1, X2 are press-fitted. In addition, hang a 1kg load on the other end of the cloth tape on the opposite side of the fastening tape, hold it for 10 seconds, and apply shear force to the pressed part to form a reliable joint.

Thereafter, the opposite end of the stainless steel flat plate and the fastening tape of the cloth tape were clamped with the jigs of the tensile tester. At this time, the tension direction of the jig at the other end of the fastening tape clamping the cloth tape on the opposite side to the sticking side is 90° with respect to the stainless steel plate.

After installing the jig on the tensile testing machine so that the final peeling angle becomes 90°, the bonded portion was peeled at a speed of 300 mm/min, and the unevenness-weighted average value measured at this time was defined as the peeling strength. In addition, the measured value is an average of 3 to 10 times of effective measured values. In addition, at the time of measurement, the sample is set so that the measurement is the measurement of the product width direction versus the product width direction. In addition, the size of the test piece is as follows. The hook surface material of the fastening tape Y1 and Y2 is 23.5±1.5mm (the front and rear direction of the product)×25mm (the product width direction), and the joint X1 and X2 are 50mm (the front and rear direction of the product)×130mm (width direction).

On the other hand, the appropriate shearing force between the fastening belts Y1, Y2 and the joints X1, X2 is designed to be 1kg-10kg, preferably 3-8kg. When it is less than 1kg, the joint is easily released; on the contrary, if it is greater than 10kg, the joint is too strong. In addition, the measuring method of this shear force is as follows. First, on a flat plate made of stainless steel, the joining portions X1 and X2 of the back sheet 12 are used as the upper surface, and are pasted with a double-sided adhesive tape. Also, secure the ends with craft tape. At this time, a blank part of the flat plate made of stainless steel remains around the joining parts X1 and X2 of the back sheet 12 .

Next, after the hook surface materials of the fastening tapes Y1 and Y2 are brought into contact with the joining parts X1 and X2 of the back sheet 12, a roller with a mass of 2 kg is used to reciprocate on their upper surfaces from the tape side, and the fastening tape Y1 The hook surface material of , Y2 and the joint parts X1, X2 of the back sheet 12 are press-bonded.

Thereafter, the blank part of the flat plate made of stainless steel and one end of the fastening bands Y1 and Y2 were fastened with the jigs of the tensile tester. At this time, the distance between the chucks was set to 50 mm. And, when clamping is completed like this, then at a pulling speed of 30mm/min, the clamp is stretched along the shearing direction of the junction X1 and X2 of the hook surface material and the back sheet 12, and the maximum shearing force is measured. In addition, the measurement value is an average of 3 to 10 times of effective measurement values. In addition, at the time of measurement, the sample is set so that the measurement is the measurement of the product width direction versus the product width direction. In addition, the size of the test piece is as follows. The hook surface material of the fastening tape Y1 and Y2 is 23.5±1.5mm (the front and rear direction of the product)×24mm (the product width direction), and the joint X1 and X2 are 50mm (the front and rear direction of the product)×130mm (width direction).

On the other hand, the pattern of the embossing for joining part formation can be set suitably as described in 1st Embodiment. In particular, as shown in FIG. 3, when embossing E is arranged along the product length direction, it is preferable from the viewpoint of stretchability and air permeability around the abdomen. Although it also varies depending on the production method, considering that the production method in which the MD direction of the back sheet 12 is generally the product width direction is considered to be the preferred production method, the embossing pattern is preferably along the direction of the embossing E when the back sheet 12 is formed. Pattern in CD direction. Here, in the present invention, the arrangement along the product length direction is not limited to the linear embossing E as shown in the example, but as shown in FIG. Also belongs to embossing along the length of the product. In addition, although not shown in the figure, the oval embossed pattern whose longitudinal direction of the product is the long side also belongs to the pattern along the longitudinal direction of the product. As long as the length direction of the embossing is along the length direction of the product.

(third embodiment)

5 and 6 show the disposable diaper Z2 of the third embodiment. Fig. 6 is a sectional view taken along line 2-2 in Fig. 5 . The unfolded disposable diaper 10 includes: a back sheet 12 constituting the outer surface of the diaper; a liquid-permeable top sheet 30 disposed on the skin side; an absorber 50 interposed between the exterior sheet 12 and the top sheet 30; Fastening tapes Y1, Y2 on both ends of the back side of the back sheet 12. Fastening tape Y1, the fastening surface of Y2 is provided with hook surface material 130A, when wearing diaper, the fastening tape Y1 of the back side, the hook surface material 130A of Y2 is joined to the arbitrary place of the abdominal side surface of back sheet 12. .

(surface sheet)

The topsheet 30 is formed in a rectangle wider than the absorbent core 56, extends slightly outward from the sides of the absorbent core 56, and is fixed to the backsheet 12 with a hot melt adhesive or the like.

The surface sheet 30 is only required to be liquid-permeable, and for example, a porous or non-porous nonwoven fabric, a porous plastic sheet, or the like can be used. In addition, there is no particular limitation on the raw material fiber of the nonwoven fabric. For example, olefins such as polyethylene and polypropylene; synthetic fibers such as polyesters, polyamides, and polyurethanes; regenerated fibers such as rayon and cupro; natural fibers such as cotton, etc., or used from these materials Two or more selected mixed fibers, composite fibers, etc. Furthermore, the nonwoven fabric may be a nonwoven fabric produced by any processing. Examples of processing methods include known methods such as spunlace, spunbond, thermal bonding, meltblown, needle punched weaving, air-through-bonding, and point bonding. For example, if softness and wrinkleability are pursued, the spunlace method is preferable, and if bulkiness and flexibility are pursued, the thermal bonding method is preferable.

In addition, the top sheet 30 may be constituted by a single sheet, or may be constituted by a laminated sheet obtained by bonding two or more sheets. Similarly, the top sheet 30 may be composed of one sheet or two or more sheets in the planar direction.

(intermediate film)

In order to quickly transfer the liquid passing through the surface sheet 30 to the absorbent core, an intermediate sheet 40 which is generally called a "second sheet" and whose liquid permeation speed is faster than the surface sheet 30 can be arranged between the surface sheet 30 and the absorbent body 50. . The intermediate sheet 40 can not only transfer the liquid to the absorbent core rapidly to increase the absorption performance by the absorbent core, but also prevent the absorbed liquid from "backflow" from the absorbent core, so that the surface sheet 30 can always be in a dry state. The intermediate sheet 40 may be omitted.

Examples of the intermediate sheet 40 include the same material as the surface sheet 30 , spunlaced nonwoven fabric, pulp nonwoven fabric, a mixed sheet of pulp and rayon, point bonding, or crepe paper. Particular preference is given to airlaid nonwovens and spunbond nonwovens.

The intermediate sheet 40 of the illustrated form may be arranged in the center narrower than the width of the absorbent core 56, or may be provided over the entire width. The length in the longitudinal direction of the intermediate sheet 40 may be the same as the length of the absorbent core 56, or may be within a shorter length centered on the liquid-absorbing region. A representative material of the intermediate sheet 40 is a nonwoven fabric excellent in liquid permeability.

(blocking envelope)

In order to stop urine or soft stools moving laterally on the surface sheet 30 and prevent side leakage, barrier wraps 60, 60 that protrude (stand up) on the use surface side are provided on both sides of the product.

The barrier cover 60 is composed of a barrier sheet 64 made of waterproof nonwoven fabric that is substantially continuous in the width direction, and an elastic elastic member 62 fixed to the barrier sheet 64 in a stretched state. A rubber band or the like can be used as the elastically expandable member 62 , and instead of providing a plurality of them as shown in FIGS. 5 and 6 , for example, one may be provided respectively.

On the inner surface of the barrier sheet 64, there is a fixing start at a position separated from the side of the surface sheet 30 (it may also be on the side of the surface sheet 30), and the part positioned at the side of the fixing start is passed through the hot melt adhesive. etc. are fixed on the side of the back sheet 12. Elastic elastic members 66 such as rubber bands are respectively provided along the front-rear direction between the sheets of the portion where the barrier sheet 64 and the back sheet 12 are opposed to each other in the fixing portion.

Around the legs, the inner side of the erected end of the blocking envelope 60 is a free part that is not fixed to the product itself, and the free part is erected by the contraction force of the rubber band 62 . When the diaper is worn, it is worn on the body in a boat shape, so the contraction force of the elastic band 62 acts, and the barrier cover 60 stands up by the contraction force of the elastic band 62 around the legs. The space surrounded by the raised portion forms a closed space for urine or soft stools. When urinating into this space, the urine is absorbed into the absorbent core 56 through the surface sheet 30, and the solid content of the soft feces is blocked by the rising portion of the barrier cover 60 to prevent it from overflowing. As for the side leakage of urine overflowing the side of the erected distal end of the erected portion, the side leakage is prevented by the stopper function of the plane abutting portion.

(Absorber)

The absorber 50 is a part that absorbs and holds liquid such as urine or loose stools. The absorbent body 50 has an absorbent core 56 and a wrapping sheet 58 that wraps at least the back and side surfaces of the absorbent core 56 . The covering sheet 58 can also be omitted. In addition, in the illustrated form, the holding sheet 80 is provided between the absorbent core 56 and the back side portion (lower side portion) of the wrapping sheet 58, but the holding sheet 80 may be omitted. The back surface of the absorber 50 is bonded to the inner surface of the back sheet 12 with an adhesive such as a hot melt adhesive.

(absorbent core)

Absorbent core 56 may use a material composed of aggregates of filaments 52, 52..., in addition to weaving short fibers such as cotton pulp.

An aggregate of filaments 52, 52... can be obtained by opening a tow (fiber bundle). As the fibers constituting the tow, for example, polysaccharides or their derivatives (cellulose, cellulose ester, chitin, chitosan, etc.), synthetic polymers (polyethylene, polypropylene, polyamide, polyester, lactamide, polyvinyl acetate, etc.), etc., particularly preferably cellulose ester and cellulose.

As the cellulose, cellulose derived from plants such as cotton, cotton linter, wood pulp, or bacterial cellulose can be used, and regenerated cellulose such as rayon can also be used. The regenerated cellulose may be spun fibers.

As the cellulose ester that can be preferably used, for example, organic acid esters such as cellulose acetate, cellulose butyrate, and cellulose propionate can be used; cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, Mixed esters such as cellulose acetate nitrate; and cellulose ester derivatives such as polycaprolactone grafted cellulose ester, etc. These cellulose esters can be used alone or in combination of two or more. The viscosity average degree of polymerization of cellulose ester is, for example, 50-900, preferably about 200-800. The average degree of substitution of cellulose ester is, for example, about 1.5 to 3.0 (eg, 2 to 3).

The average degree of polymerization of cellulose ester is, for example, about 10 to 1000, preferably about 50 to 900, more preferably about 200 to 800, and the average degree of substitution of cellulose ester is, for example, about 1 to 3, preferably about 1 to 2.15, More preferably, it is about 1.1 to 2.0. The average degree of substitution of cellulose ester can be selected from the aspects of improving biodegradability and the like.

As the cellulose ester, organic acid esters (for example, esters of organic acids having about 2 to 4 carbon atoms) are preferred, and cellulose acetate is particularly preferred. The degree of acetylation of cellulose acetate is usually about 43% to 62%, and especially about 30% to 50%, since it is excellent in biodegradability, it is preferable. A particularly preferred cellulose ester is cellulose diacetate.

The fibers constituting the tow may contain various additives such as heat stabilizers, colorants, oils, yield improvers, whiteness improvers, and the like.

The fineness of the fibers constituting the tow can be, for example, 1 to 16 deniers, preferably 1 to 10 deniers, more preferably 1 to 6 deniers. The fibers constituting the tow may be non-crimped fibers. The degree of crimping of crimped fibers can be, for example, 5 to 75 crimps per inch, preferably 10 to 50 crimps, and more preferably about 15 to 50 crimps. Also, crimped fibers that are uniformly crimped are often used. When crimped fibers are used, a bulky and lightweight absorbent core can be produced, and a high-integrity tow can be easily produced by entanglement between fibers. The cross-sectional shape of the fibers constituting the tow is not particularly limited, and may be, for example, any one of circular, oval, irregular (for example, Y-shaped, X-shaped, I-shaped, R-shaped, etc.) or hollow. kind of shape. The fibers constituting the tow are used in the form of a tow (fiber bundle) formed by bundling, for example, about 1,000 to 1,000,000, preferably about 2,000 to 1,000,000 single fibers. The fiber bundle is preferably constituted by bundling about 1,000 to 1,000,000 continuous fibers.

The cellulose diacetate tow tulle preferably used in the present invention is commercially available from Celanese Corporation, Daicel Chemical Industry, and the like. The density of the tulle of tow of cellulose diacetate is about 0.5 g/cm ³ and the total weight is 400-600 kg. Extract the tow from the tulle, and open it into a wide ribbon according to the desired size and bulkiness. The opening width of the tow is arbitrary, for example, the width can be 50-2000mm, and the width of the absorbent core of the product is preferred. It is about 50-300mm. In addition, the density of the absorbent core can be adjusted by adjusting the degree of opening of the tow.

(superabsorbent polymer particles)

Preferably, as shown in Figure 6, the absorbent core 56 includes superabsorbent polymer particles 54, 54... . Furthermore, it is preferable that the absorbent polymer particles (SAP particles) are substantially dispersed in the aggregate of the filaments 52, 52... in the entire thickness direction at least in the liquid storage area. The enlarged view of main parts in FIG. 6 conceptually shows a state of being substantially dispersed along the entire thickness direction.

In the case where there are no or few SAP particles on the upper, lower, and middle portions of the absorbent core 56, it cannot be said to be "dispersed in the entire thickness direction". Therefore, "dispersion along the entire thickness direction" includes "inhomogeneity" in the upper, lower and/or middle parts in addition to "uniformly" dispersed in the aggregate of filaments along the entire thickness direction, but A form in which each part of the upper part, the lower part, and the middle part is dispersed. Moreover, it is not excluded: some SAP particles do not penetrate into the aggregate of long filaments 52, 52..., but remain on the surface; some SAP particles penetrate through the aggregate of long filaments 52, 52... , the form on the covering sheet 58 ; or the form on the holding sheet 80 .

The superabsorbent polymer particles 54 include "particles" and "powders". The particle size of the superabsorbent polymer particles 54 can be used as it is in such a disposable diaper, and is 1000 μm or less, particularly preferably 150 to 400 μm. The material of the superabsorbent polymer particles 54 is not particularly limited, but particles having a water absorption of 40 g/g or more are preferable. As the superabsorbent polymer particles 54, there are starches, celluloses, or synthetic polymers, etc., and starch-acrylic acid (salt) graft copolymers, saponified products of starch-acrylonitrile copolymers, and carboxymethyl fibers can be used. Sodium cross-linked product or acrylic acid (salt) polymer, etc. As the shape of the superabsorbent polymer particles 54 , generally used granular particles are preferable, but particles of other shapes may be used.

As the superabsorbent polymer particles 54, it is preferable to use particles having a water absorption rate of 40 seconds or less. When the water absorption speed exceeds 40 seconds, the liquid supplied into the absorbent core 56 tends to flow back out of the absorbent core 56, that is, so-called backflow tends to occur.

In addition, as the superabsorbent polymer particles 54, particles having a gel strength of 1000 Pa or more are preferably used. Thereby, even when forming the bulky absorbent core 56, the sticky feeling after liquid absorption can be suppressed effectively.

The distribution amount per unit area of the superabsorbent polymer particles 54 can be appropriately determined according to the absorption amount required for the use of the absorbent core 56 . Therefore, it cannot be generalized, but it can be set at 50 to 350 g/m ² . When the distribution per unit area of the polymer is 50 g/m ² or less, the weight of the polymer can prevent the use of synthetic continuous fibers from being difficult to achieve the lightweight effect. If it exceeds 350 g/m ² , not only the effect will be saturated, but also an uncomfortable gritty feeling will be caused due to the excess of superabsorbent polymer particles 54 .

The scattering density or the scattering amount of the superabsorbent polymer particles 54 in the planar direction of the absorbent core 56 can be adjusted, if necessary. For example, the fluid discharge site may spread more than other sites. Considering the differences between men and women, men's articles can increase the spray density (amount) on the front side, while women's articles can increase the spray density (amount) in the central part. Moreover, you may provide the part where a polymer does not exist in the plane direction of the absorbent core 56 locally (for example, dotted).

According to need, a plurality of superabsorbent polymer particles 54 with different particle size distributions can be prepared and supplied sequentially in the thickness direction, and particles with a small particle size distribution can be distributed on the lower side of the absorbent core 56, and particles with a smaller particle size distribution can be distributed on the upper side. Particles with large diameter distribution.

The ratio of superabsorbent polymer particles 54 to continuous fibers influences the absorbent properties. The superabsorbent polymer particle/continuous fiber weight is preferably 1-14, particularly preferably 2-9, as the weight ratio in the area of the absorbent core 56 that directly receives liquid in a plane area of 5 cm×5 cm.

(wrap sheet)

When using the wrapping sheet 58, thin paper, especially crepe paper, nonwoven fabric, multilayer nonwoven fabric, sheet with small holes, etc. can be used as the material. However, a sheet from which superabsorbent polymer particles do not come out is preferable. In the case of using non-woven fabric instead of crepe paper, hydrophilic SMMS (spunbond/meltblown/meltblown/spunbond) nonwoven fabric is particularly preferred, and its material can be polypropylene, polyethylene/polypropylene, and the like. The basis weight is preferably 5 to 40 g/m ² , particularly preferably 10 to 30 g/m ² .

For this covering sheet 58, in addition to the method of covering the aggregate of continuous fibers 52, 52... and the entire layer of superabsorbent polymer particles 54, 54... as shown in FIG. How to wrap the back and sides of the layer. In addition, although not shown, it is also possible to adopt the following method: the upper surface and side surfaces of the absorbent core 56 are covered with crepe paper or non-woven fabric, and the lower surface is covered with a liquid-impermeable sheet such as polyethylene; The surface is covered with crepe paper or non-woven fabric, and the side and bottom are covered with a liquid-impermeable sheet such as polyethylene (these materials become the constituent elements of the wrapping sheet). If necessary, the aggregate of continuous fibers 52, 52 . , is not ideal because it is difficult to prevent superabsorbent polymer particles from moving.

(hold sheet)

When the holding sheet 80 is provided, the superabsorbent polymer particles 54 are interposed between the holding sheet 80 and the upper surface of the absorbent core 56S by scattering or the like. The superabsorbent polymer particles 54 may penetrate the aggregate of the continuous fibers 52 at the time of supply to the aggregate of the continuous fibers 52 or in a subsequent step, or during distribution before use by consumers. The unevenness formed by the superabsorbent polymer particle group penetrating the aggregate of continuous fibers causes an uncomfortable gritty feeling when touched by the consumer's hand. Here, it is preferable to interpose the holding sheet 80 having the performance of holding the superabsorbent polymer 54 between the absorbent core 56 and the wrapping sheet 58 . The retaining sheet 80 strengthens the stiffness that is insufficient only by the wrapping sheet 58 such as thin paper (crepe paper), so as to reduce or prevent the uncomfortable feeling when the consumer uses it.

The material of the holding sheet 80 is not particularly limited as long as it can hold the superabsorbent polymer 54 . Specifically, for example, non-woven fabrics, crimped pulp, low-absorbency cotton fibers (for example, undegreased cotton fibers, degreased cotton fibers, rayon fibers obtained by treating rayon fibers with a water-repellent or water-repellent agent) fiber, etc.), polyethylene fiber, polyester fiber, acrylic fiber, polypropylene fiber, silk, cotton, hemp, nylon, polyurethane, acetate fiber, etc.

When the holding sheet 80 is made of non-woven fabric, the holding sheet 80 has a compression energy of 0.01 to 10.00 gfcm/cm ² , preferably 0.01 to 1.00 gfcm/cm ² , and a compression elasticity of 10% based on the KES test. ~100%, preferably 70%~100% non-woven fabric is suitable.

As mentioned above, the reason why the holding sheet 80 is provided is to hold, for example, the superabsorbent polymer 54 that falls out (protrudes) downward from the absorbent core 56 . Therefore, since the user contacts the detached superabsorbent polymer particles 54 through the wrapping sheet 58 and the holding sheet 80, an uncomfortable gritty feeling is not given to the user. In particular, a nonwoven fabric having the above-mentioned compressive energy and compressive elasticity can fully exhibit this function.

In addition, since the detached superabsorbent polymer 54 is held by the holding sheet 60 and does not move on the wrapping sheet 58, uneven absorbency does not occur. In particular, in order to prevent the superabsorbent polymer particles 54 from moving on the holding sheet 80, an adhesive hot-melt adhesive or the like may be applied to the holding sheet 80 in advance. Furthermore, it is also possible to prevent the superabsorbent polymer particles 54 from moving on the holding sheet 80 by making the upper surface (the surface facing the use surface side) of the holding sheet 80 rough. Examples of roughening or fluffing methods for this purpose include forming a non-mesh surface other than a mesh surface, embossing, needle-punching, and brushing when producing a nonwoven fabric.

The holding sheet 80 may be provided under the absorbent core 56 as shown in FIG. 6 , or may be rolled up from the side of the absorbent core 56 and extended to the upper surface of the absorbent core 56 (not shown). In addition, a plurality of holding sheets 80 may be stacked and used.

The above example is an example in which the holding sheet 58 is provided between the absorbent core 56 and the back side of the wrapping sheet 58, but the holding sheet may also be provided on the back side of the wrapping sheet 58 (this method is not shown). If the holding sheet is provided on the back side of the absorbent core 56, the uncomfortable gritty feeling when touching the product from the back side can be reduced or eliminated.

(fastening strap)

The fastening tapes Y1 and Y2 are provided with a fastening base material 130C whose base is joined to the diaper and whose front end side is not fixed as a free end, and a hook surface material 130A joined to the inner surface of the front end side. The fastening substrate 130C can be formed of plastic, multi-layer non-woven fabric, paper, and the like. The hook surface material 130A is bonded to the fastening base material 130C by means of an adhesive, and cannot be peeled off. The outer surface side of the hook material 130A has a plurality of engaging protrusions 130D. As the shape of the engaging protrusion 130D, as shown in FIG. J-shaped engaging protrusions combined in a back-aligned manner), etc., but any shape may be used. A shape that is easily entangled with the fibers of the back sheet 12 is preferable, for example, the engaging protrusions 130D in a T-shape, a J-shape, a T-shape, or a double J-shape. The fastening tapes Y1 and Y2 are folded toward the surface sheet 30 in a product state, and the hook surface material 130A is bonded to the side nonwoven fabric in a detachable manner.

As the constituent fibers of the exterior nonwoven fabric 12B of the back sheet 12 to which the fastening tapes Y1 and Y2 are fixed, in addition to synthetic fibers such as olefins such as polyethylene or polypropylene, polyesters, and polyamides, artificial fibers can also be used. Natural fibers such as regenerated fibers such as silk or cupro, and natural fibers such as cotton can be non-woven fabrics obtained by appropriate processing methods such as spunlace, spunbond, thermal bonding, air-through-netting, and needle-punched weaving. spinning.

On the opening side of the abdominal side, a fastening position display sheet 74 is provided on the inner surface side of the back sheet 12. On this fastening position display sheet 74, the hook surface that becomes the fastening belt Y1, Y2 is implemented by printing or the like. The design of the location target where the material 130A is fastened can be recognized from the outside through the back sheet 12 . In order to improve air permeability, the fastening position display sheet 74 can be omitted, but as the material of the fastening position display sheet 74, it is preferable to use a material such as nonwoven fabric or paper with air permeability.

(Elastic stretch parts such as rubber bands)

The unfolded disposable diaper Z2 is closely attached to the body by adjusting the fastening positions of the fastening belts Y1 and Y2. Therefore, the back sheet 12 is usually provided with elastic elastic parts such as rubber bands along the waist end or around the legs. No elastic expansion and contraction member is provided at the portion overlapping with the absorber 50, and this structure is also adopted in the illustrated manner.

(back sheet)

The back sheet 12 is a part for supporting the absorbent body 50 and being worn by a wearer. The back sheet 12 is formed into an hourglass shape in which the central portions in the front-rear direction of both sides are contracted, and this is a portion where the wearer's legs enter. The absorber 50 and the top sheet 30 are provided at predetermined positions on the inner side of the back sheet 12, and are fixed by an adhesive such as a hot melt adhesive. In addition, predetermined locations on the outer surface of the back sheet 12 serve as joining portions X to which the hook surface materials 130A of the fastening tapes Y1 and Y2 are joined. The engaging portion X is located on the opposite side to the fastening tapes Y1, Y2 on the back side and the ventral side, and its position and size can be set arbitrarily as long as it can engage the hook material 130A. Usually, the size of the joining portion X is a rectangular range with a length of 20-80 mm in the front-rear direction and a width of 150-300 mm. 50mm, and located in the center of the width direction of the product.

As described in the first embodiment, etc., the hydrophobic sheet 12A on the inner surface side and the nonwoven fabric sheet 12B on the outer surface side are used as the main body, and the interlayer nonwoven fabric is interposed between them and laminated if necessary. , bonded by a hot-melt adhesive H, thereby constituting the back sheet 12 . In the third embodiment, the nonwoven fabric is used as the hydrophobic sheet 12A, so that the backsheet 12 is composed of only the nonwoven fabric, and a polyethylene film is not provided between the inner surface of the backsheet 12 and the outer surface of the absorber 50. A liquid-impermeable sheet made of a resin film such as a water-insoluble material is used as the hot-melt adhesive H for bonding the hydrophobic sheet 12A and the non-woven fabric sheet 12B, and the water-insoluble The hot-melt adhesive H is applied to the portion of the back sheet 12 overlapping with the absorber 50 and its surroundings so that the water pressure resistance of the applied portion reaches 400 mmAq or more. An example of the back sheet 12 is shown in Fig.7 (a), (b), respectively. When the water pressure resistance is less than 400mmAq, the continuity of the liquid shielding is insufficient, and the liquid component gradually leaks out, and leakage may occur even during the normally set wearing time. The water pressure resistance is preferably 700 to 1000 mmAq. If the water pressure resistance is too high, the air permeability may decrease, so it is not ideal.

The types of the nonwoven fabric forming the hydrophobic sheet 12A and the nonwoven fabric 12B for exterior and the type of the water-soluble hot-melt resin H are not limited as long as they have a water pressure resistance within this range. As the nonwoven fabrics 12A and 12B, the A single-layer non-woven fabric with a fiber composition of less than 1.2 dtex, especially 0.5-0.9 dtex, and a fiber basis weight of 15 g/m ² or more, especially 20-25 g/m ² , or a fiber basis weight of 10 g/m ² or more, In particular, it is a melt-blown non-woven fabric of 15-25 g/m ² . And, more preferable non-woven fabrics 12A, 12B are constituted by laminating two or more fiber layers, at least one layer is composed of fibers less than 1.2 dtex, especially 0.5 to 0.9 dtex, and the fiber basis weight is A laminated nonwoven fabric of 15 g/m ² or more, especially 18 to 22 g/m ² ; or a fiber basis weight in which the meltblown layer is included in the middle layer is 10 g/m ² or more, especially 15 to 25 g/m 2 ² SMS non-woven fabrics, especially SMMS non-woven fabrics and other non-woven fabrics with multi-layer melt-blown layers. The fibers of the nonwoven fabrics 12A and 12B are too thick and the basis weight of the fibers is too small, and even if the coating amount of the hot-melt resin H is increased, the liquid-blocking properties may still be insufficient. If the fibers of the nonwoven fabrics 12A and 12B are too thin, the strength will be insufficient, and the sheet 70 may be damaged. If the fiber basis weight of the nonwoven fabrics 12A and 12B is too large, rigidity and weight may increase unnecessarily, which may degrade the wearing feeling. The entire back sheet 12 preferably has a basis weight of 15 to 50 g/m ² and a thickness of 0.01 to 0.5 mm. In addition, the nonwoven fabric forming the hydrophobic sheet 12A and the nonwoven fabric for exterior 12B can basically use the same material, but it is not necessary to use the same material, and an appropriate material can be selected individually as needed.

In particular, the ideal structure is to overlap the hydrophobic sheet 12A and the non-woven fabric sheet 12B on the back sheet 12, bond the sheets to each other via the water-insoluble hot-melt resin H, and fix the elastic elastic members on both sides in a stretched state. Between the sheets 12A, 12B, the back sheet 12 is tightly attached to the wearer by its shrinkage force. In this case, the water-insoluble hot-melt resin H not only functions to improve the liquid-shielding properties of the back sheet 12, but also functions to join the hydrophobic sheet 12A and the nonwoven fabric sheet 12B, and to fix the elastic elastic member on the hydrophobic surface. The function between the sex sheet 12A and the non-woven sheet 12B. As the elastic stretchable member, a rubber band or a strip of elastic foam can be used, and it is preferable to arrange a plurality of rubber bands collectively or with gaps therebetween.

As the water-insoluble hot-melt resin H, one that is insoluble in water among those commonly used as hot-melt adhesives in this technical field can be used, for example, AFX-088A (manufactured by Niuta Findrey Co., Ltd.). Furthermore, as the water-insoluble hot-melt resin H, a hydrophilic resin can be used.

The water-insoluble hot-melt resin H only needs to be coated on either one of the hydrophobic sheet 12A and the nonwoven fabric sheet 12B, but it may also be coated on both the front and the back. However, it is preferable to coat the surface not exposed to the outside.

The coating amount of the water-insoluble hot-melt resin H can be appropriately set, and in the case of using the above-mentioned fineness and basis weight of the nonwoven fabric, it is preferably 5 to 30 g/ ^m2 or more within the range where at least water resistance is ensured, Especially preferably 8 to 10 g/m ² . If the amount of application is insufficient, the liquid will slowly permeate, so there is a possibility that the continuity of the liquid covering may be insufficient. If the coating amount is too large, the air permeability may decrease, and the cost performance may decrease, so it is not preferable.

The coating pattern of the water-insoluble hot-melt resin H is not particularly limited, and known coating methods such as curtain coating, spiral coating, spiral fiber gun coating (method of narrowing the spiral interval), and slot coating can be used. , the pattern can be regular or irregular, but preferably the adhesive can be applied in a regular pattern.

As a particularly preferred pattern, from the aspect of ease of manufacture, it is preferable to set a pattern in which a plurality of rows of continuous coating lines H are arranged at predetermined intervals in the front-rear direction or the width direction of the diaper as shown in FIG. 7( a), or as shown in FIG. 7( b ). ) as dot-shaped coating points H are arranged in a scattered dot-shaped pattern. In this case, it is preferable that the total bonding area is 90% or more and less than 100%, and the line width W (one) of the coating line H is 0.1 to 3 mm, or the area (one point) of the application point H is 0.05 to 5 mm ² . If the total coating area is too small, even if the non-woven fabrics 12A and 12B have high liquid-blocking properties, the liquid-blocking continuity will still be insufficient; if the line width or dot area is too narrow, no matter the total coating area, coating No matter how much the amount is, the continuity of liquid covering will easily become insufficient; if the line width or dot area is too wide, the air permeability will easily deteriorate. Particularly preferable ranges are that the total coating area is 95% to 97%, the width of the coating line H is 1 to 2 mm, and the area of the coating point H is 2 to 4 mm ² .

In particular, it is desirable to locally increase the coating amount of the water-insoluble hot-melt resin H on the joining portion X of the back sheet 12 compared with other portions, and relatively improve the durability of the hook surface material 130A against peeling. . As this specific method, in addition to the method of double-coating the water-insoluble hot-melt resin H, a method of partially increasing the coating amount without repeated coating may be employed.

In the case where the water-insoluble hot-melt resin H is double-coated on the junction X of the back sheet 12, the coating pattern can be appropriately determined. In order to further increase the strength, it is preferable to form the pattern coated first in the front-back direction of the diaper or A pattern of multiple rows of continuous coating lines is arranged at predetermined intervals in the width direction, or dot-shaped coating points are arranged in a pattern of scattered dots, and the pattern of subsequent coating is formed as a pattern intersecting the pattern of previous coating. These pattern coatings can be achieved by spiral patterns such as spiral coating, spiral fiber gun coating, etc., curtain coating, bead coating, and the like.

8 to 10 show combinations of various patterns. In the example shown in FIG. 8, as the pattern of coating earlier, a linear pattern in which continuous coating lines H are arranged at predetermined intervals in the front and rear direction of the diaper is used; in the example shown in FIG. 9, as the pattern of coating earlier, , a linear pattern in which continuous coating lines H are arranged at predetermined intervals in the width direction of the diaper is used; in the example shown in FIG. Dot pattern.

Moreover, in the examples shown in these FIGS. 8 to 10 , in (a) figure, as a post-coating pattern, the following pattern is adopted, that is, a pattern parallel to the slope direction intersecting with the front-back direction or the width direction of the diaper. A plurality of coating lines Hs are provided, and a diagonal mesh-shaped pattern of a plurality of coating lines Hs line-symmetrical with respect to the front-back direction of the diaper is provided in parallel. In addition, in the figure (b), as a post-coating pattern, a helical pattern Hp such as a spiral coating, a spiral fiber gun coating, or the like is used. In addition, in the figure (d), as the post-coating pattern, a pattern in which two wave-shaped coating lines Hw are provided with a phase shift of 180 degrees is employed. In addition, in (e) figure, as the pattern of post-coating, the pattern which provided the wave-shaped coating line Hw of several in parallel is employ|adopted. In addition, in the figure (f), as the pattern of the post-coating, a pattern in which a plurality of concentric coating lines Hc are provided is employed.

In addition, in the figure (c) in the example shown to FIG. 8 and FIG. 9, the pattern which provided the dot-shaped application point Hd in the shape of a dot was used as the pattern of post-coating. And, in (c) figure among the example shown in Fig. 10, as the pattern of post-coating, adopted the linear pattern that a plurality of continuous coating lines Hf are arranged at predetermined intervals in the front-back direction of the diaper; (g) In the figure, as the post-coating pattern, a linear pattern in which a plurality of continuous coating lines Hk are provided at predetermined intervals in the width direction of the diaper is used.

(other)

In addition, although not shown, each component part of a diaper can be mutually fixed mutually by the solid coating of a hot-melt adhesive etc., knife coating, spiral coating, or spiral fiber gun coating, etc. Furthermore, within the scope of the present invention, partial configurations of other embodiments may be adopted in this third embodiment, and partial configurations of this third embodiment may be applied to other embodiments.

<Embodiment of Manufacturing Method of Back Sheet>

Next, an embodiment of a method for producing a back sheet will be described in detail with reference to the drawings. Fig. 12 is a schematic diagram of a method for producing a back sheet for an absorbent article of the present invention. At the time of production, first, the hot-melt adhesive H is continuously or intermittently placed on the continuous sheet-shaped hydrophobic sheet 12A conveyed from the front stage of the take-up roll S1 or the like using the coater 5 or the spreader. Next, the continuous sheet-shaped nonwoven fabric sheet 12B conveyed from the front stage of the take-up roll S2 and the like is superimposed on the hydrophobic sheet 12A provided with the hot-melt adhesive H, and is sandwiched between the two sheets. In the state of the hot-melt adhesive material, two sheets are laminated.

Although not shown, other material sheets formed of non-woven fabrics or films are partially or wholly sandwiched between the hydrophobic sheet and the non-woven fabric sheet. In addition to the non-woven fabric sheet of other material sheets, another continuous other material sheet can also be supplied between the hydrophobic sheet and the non-woven fabric sheet. In the case of a partial arrangement, it is only necessary to intermittently cut the supplied continuous other material pieces. When the sheet is simply multilayered, it can be carried out according to existing techniques. In addition, in this case, a hot-melt adhesive may or may not be provided between the other material sheet and the nonwoven fabric sheet, but it is preferable to provide a hot-melt adhesive.

As the hydrophobic sheet 12A, the nonwoven fabric sheet 12B, and the other material sheet 12C, the same materials as those described in the first to third embodiments can be used.

The coating amount of the hot melt adhesive H used between the hydrophobic sheet 12A and the nonwoven fabric sheet 12B is 0.5 to 30.0 g/m ² , preferably 1.0 to 25.0 g/m ² , particularly preferably 3.0 to 15.0 g/m 2 . g/m ² . Furthermore, in the case of constituting multiple layers using other material sheets, the amount of the hot-melt adhesive between the outermost layer and the backmost layer is preferably within this range. When it is less than 0.5 g/m ² , the effect of the adhesive cannot be obtained; and when the coating amount exceeds 30.0 g/m ² , the flexibility of the back sheet 12 is impaired.

In addition, known coaters such as a slot coater and a curtain coater can be used as the coater 5 for applying the hot-melt adhesive H. Also, the coating may be performed by spraying a hot melt adhesive, or by spraying using a spray nozzle. The application method is not particularly limited.

The laminated sheet 12' laminated in this way is supplied to the embossing processing device 3, which has embossed lines formed on the entire surface, and performs embossing processing to thermally press the laminated sheets. Convex embossing roll 3A for flower convex part. In addition, although the embossing roll was used in this form, in this invention, heat-compression-bonding may be performed with the simple heating roll, without using an embossing roll. In addition, in this embodiment, the method of using the embossing roll as the thermocompression bonding unit is mainly described, but the thermocompression bonding unit in the present invention is not limited to the method using the embossing roller, for example, ultrasonic bonding may be used.

Embossing refers to pressing the nonwoven fabric sheet 12B side with the convex embossing roll 3A. The roll 3B facing the convex embossing roll 3A may be a concave embossing roll formed with a concave portion corresponding to the convex portion of the convex embossing roll, or may be soft enough to press the convex portion of the convex embossing roll. The permanent rubber roller is not particularly limited. The bonding point area of the convex part of the convex embossing roll, that is, the embossing area, is 5% to 50%, preferably 5% to 40%, particularly preferably 10% to 30%. When the embossed area is less than 5%, the adhesive strength is insufficient, and when it is larger than 50%, the embossed sheet may become hard and the touch may be impaired.

In addition, the embossing pressure during embossing is preferably 3 to 20 kgf/cm ² . When it is less than 3kgf/cm ² , when the coating amount of the adhesive is in the above range, the adhesion between the hydrophobic sheet 12A and the nonwoven fabric sheet 12B is insufficient; when it is greater than 20kgf/cm ² , the nonwoven fabric sheet 12B is cured, which may cause its haptics to be impaired. In addition, since the embossing pressure also affects the processing speed, it can be appropriately changed within the range not departing from the idea of the present invention.

Here, for example, when used as a back sheet of a disposable diaper as an absorbent article, the peel strength between the hydrophobic sheet 12A and the nonwoven fabric sheet 12B is such that it cannot be peeled substantially. That is, it is firmly bonded so that when it is forced to peel off, the back sheet may be damaged. It is the same even when 12 C of other material sheets are interposed.

Example

Example 1

In the manufacturing method (Example) which concerns on this invention, and another manufacturing method (comparative example), it tested whether it wound up to an embossing roll. The test results are listed in Table 1 below.

The test was carried out as follows, using a hot-melt adhesive with the physical properties shown in the following Table 1, an air-laid non-woven fabric sheet (PE/PET) manufactured at a basis weight of 20 g/ ^m2 and a polyethylene film with a thickness of 25 μm After the sheets are bonded, embossing is applied using embossing rolls.

The embossing conditions were set as follows: embossing pressure 7 kgf/cm ² , gap 0.3 mm, sheet traveling speed 165 m/min, pressing time 0.9 seconds/sheet, and continuous operation time 20 hours. As an evaluation, the number of windings on the discharge side of the embossing roll was measured.

[Table 1]

Name of hot melt adhesive Composition of hot melt adhesive Cyclic adhesion test (25°C) (N/25mm) Cyclic adhesion test (40°C) (N/25mm) Softening point (℃) Melt viscosity at 160°C (mPa·S) Winding on embossing roller (times) Example 1 ME100 SBS Petroleum Resin-based Paraffin-based No No 84 3700 0 Example 2 AFX-402 SBS Petroleum Series Paraffin Series No 2.3 88 5300 0 Comparative example 1 JM5236WZP SIS+SBS petroleum system paraffin system 5.5 5.5 95 6800 9 Comparative example 2 ME190E SIS+SBS petroleum resin series natural modified series paraffin series 12.5 12.5 83 3700 15 Comparative example 3 JM5215WZP SIS+SBS block polymer Petroleum-based paraffin-based 24.5 24.5 93 5188 18

As shown in Table 1, in the production method (Example) according to the present invention, winding to the embossing roll was not observed, but winding was confirmed in another production method (comparative example). The results show that wrapping on the embossing roll is prevented by the invention.

Here, it should be noted in Table 1 that the softening point and 160-degree melt viscosity involved in each example have no correlation with winding. When the melt viscosity is high, the softening point is low, and the viscosity is high especially at the temperature at which embossing is applied, it is expected that curling will occur, but as shown by the above test results, there is actually no relationship. In addition, in the cyclic blocking test, the wrapping of the hot-melt adhesive when embossing is performed by an embossing roll having unevenness is not used as an index. Furthermore, the special significance of this test result is that, from the results of the peel strength in the cyclic adhesion test at 40° C. different from the embossing temperature, it can be known that the curling when the overflow from the nonwoven fabric surface is suppressed and the embossing is applied can be known. The scope of occurrence of winding.

Example 2

Next, the presence or absence of embossing, the ratio of embossing, and the presence or absence of a hot-melt adhesive were different, and the examples and comparative examples of the present invention were produced, and the bending value and adhesive strength of the KES were measured, and the flexibility was evaluated. wait. Each embodiment and comparative example are respectively the following three ways: for example, the air-laid non-woven fabric sheet (PE/PET) and the polyethylene film sheet with a thickness of 25 μm manufactured with a basis weight of 20g/ ^m2 are heated only with heat. A method of bonding with a melt adhesive; a method of bonding with only embossing; a method of bonding by applying embossing with an embossing roller after bonding with a hot melt adhesive. Table 2 below shows other details such as which method each Example and Comparative Example belongs to, the amount of hot melt adhesive used, the amount of embossing, and the like. In addition, the conditions for applying embossing were embossing pressure 7 kgf/cm ² , gap 0.3 mm, sheet traveling speed 165 m/min, and pressing time 0.9 seconds/sheet.

Here, the bending measurement value of KES is as follows. Using a pure bending tester (manufactured by IPROS: KES-FB-2AOUT-A), a sample cut into a length of 200mm and a width of 200mm was placed on the above-mentioned testing machine, and the DFE sensitivity of 20 was measured. , Curvature range 0.0 ~ 0.5cm ^-1 under bending value.

In addition, the sensory evaluation was as follows: when the tester actually touched the sample, the sample felt soft was evaluated as ◯, and the sample felt lacking in softness was evaluated as x.

In addition, the adhesive strength (A) between a film sheet and a nonwoven fabric sheet was measured using the tensile tester (AOUTGRAPH AGS-G100N by Shimadzu Corporation). The measurement method is as follows. Make a sample (back sheet) cut into 25mm×130mm, and peel off 5cm along the length direction in advance by cold spraying. Conditions, the adhesive strength (peel strength) when peeling a length of 30 mm from the above-mentioned peeling port in a tensile test was measured. In addition, the measured value is obtained as follows: As a sample, two kinds of samples whose longitudinal direction is the product vertical direction and the sample whose longitudinal direction is the product transverse direction are prepared, respectively measured, and the average value of the obtained values is obtained as a measured value.

In addition, the peel strength (B) between the nonwoven fabric sheet and the hook surface material is measured as follows. After superimposing the hook surface material cut into the same size on the sample (back sheet) cut into 50 mm × 130 mm, a 2 kg roll is used. Roll on it, squeeze the hook surface material onto the non-woven fabric sheet, further add 1 kg in the shearing direction, and continue for 10 seconds to engage the non-woven fabric sheet and the hook surface material to make a test piece. And this sample was measured in the same manner as the measurement of the adhesive strength (A), and the measured value was computed.

[Table 2]

As can be seen from Table 2, in this test, the unfolded absorbent article of the present invention does not have to worry about interlayer detachment due to detachment during fastening, and exhibits excellent flexibility compared with the comparative example.

Industrial Applicability

The disposable diaper of the present invention can be used as an unfolded disposable diaper.

In addition, the production method of the present invention can be used for the production of back sheets of other absorbent articles such as unfolded disposable diapers, pants-type disposable diapers, sanitary napkins, or urine pads, and can also be used for surgical gowns, Manufacture of exterior sheets used in disposable products such as packaging materials, especially products that require good liquid impermeability and skin contact feeling.

Claims (14)

1. An unfolded absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body interposed between the two sheets, and on the left and right sides of either the back side or the ventral side. A fastening belt is provided on the side part, and part or all of the fastening belt is formed by the hook surface material of the surface buckle, and the hook surface material is joined between the left and right side parts of the abdominal part or the back side part. on the joint portion for wearing, the unfolded absorbent article is characterized in that, The back sheet is formed by laminating a hydrophobic sheet made of a hydrophobic resin and a nonwoven fabric sheet constituting the outer surface of the article with a hot-melt adhesive interposed therebetween, and then thermally pressing. The adhesive strength between the nonwoven fabric sheet and the nonwoven fabric sheet is higher than the peel strength when the hook surface material is fastened to the nonwoven fabric sheet, and the measured value in the KES bending test is 0.05 to 0.50 g·cm ² /cm. 2. The unfolded absorbent article according to claim 1, wherein the amount of the hot-melt adhesive used between the hydrophobic sheet and the nonwoven fabric sheet is 0.5 to 30.0 g/m ² . 3. The unfolded absorbent article according to claim 1 or 2, wherein after laminating the hydrophobic sheet and the nonwoven fabric sheet with the hot melt adhesive interposed therebetween, the nonwoven fabric sheet The cloth side is located on the convex roll side of the embossing roll, and they are thermally pressed together while embossing. 4. The unfolded absorbent article according to any one of claims 1 to 3, wherein, prior to the thermocompression bonding, an interlayer with a non-woven sheet is interposed partly or entirely between the hydrophobic sheet and the nonwoven sheet. They differ from other material sheets. 5. The unfolded absorbent article according to claim 4, wherein the other material sheet is a nonwoven fabric made of a hydrophobic resin. 6. The unfolded absorbent article according to claim 4 or 5, wherein the thermocompression bonding is performed only on the joining portion. 7. The unfolded absorbent article according to claim 6, wherein the junction part is composed of a pair of left and right junction parts, and the junction parts are arranged separately at least at the widthwise center of the product, and the hook surface material is located at the separated part. The engagement on is not sufficient for use. 8. The unfolded absorbent article according to any one of claims 4 to 7, wherein the other material sheet is arranged only on the joining portion and its periphery. 9. The unfolded absorbent article according to any one of claims 1 to 8, wherein the coating pattern of the hot-melt adhesive is continuous coating in multiple rows at predetermined intervals in the front-back direction or the width direction of the article. A line pattern, the width of the above-mentioned coating line is 0.1-3 mm, and more than 90% of the area of the above-mentioned hydrophobic sheet is coated; or, The coating pattern of the above-mentioned hot-melt adhesive is a dot-shaped coating point arranged in a scattered pattern, the area of the above-mentioned coating point is 0.05-5 mm ² , and more than 90% of the area of the above-mentioned hydrophobic sheet is coated. cloth. 10. The unfolded absorbent article according to any one of claims 1 to 9, wherein the hydrophobic sheet is a nonwoven fabric made of a hydrophobic resin, and the hot-melt adhesive is made of a water-insoluble hot-melt resin. , and at least in the range where the hot-melt adhesive is sandwiched, the water pressure resistance of the back sheet is 400 mmAq or more. 11. The unfolded absorbent article according to any one of claims 1 to 10, wherein the application amount of the hot-melt adhesive in the joining portion is locally increased compared with other portions. 12. The unfolded absorbent article according to claim 10 or 11, wherein the nonwoven fabric used in the hydrophobic sheet is a single-layer nonwoven fabric or a laminated nonwoven fabric having two or more layers, at least one of which is The layer is composed of fibers less than 1.2 dtex, and the fiber basis weight is above 15 to 25 g/m ² . 13. A method for producing a backsheet for an absorbent article, for producing the backsheet used in an absorbent article in which an absorbent body is interposed between a liquid-permeable topsheet and a liquid-impermeable backsheet, wherein: After laminating the hydrophobic sheet made of hydrophobic resin and the non-woven fabric sheet with a hot-melt adhesive interposed, the sheets are heat-compressed. The hot-melt adhesive is specified in JIS Z 0237 The peel strength at 40° C. in the cycle adhesion test is 0.0 to 5.0 N/25 mm. 14. The method for producing a back sheet for an absorbent article according to claim 13, wherein said thermocompression bonding is carried out while performing embossing at an embossing pressure of 3 to 20 kgf/ ^cm2 .

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