JP4804021B2 - Absorbent articles - Google Patents

Description

  The present invention relates to absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads.

  Absorbents for absorbent articles using continuous filament spread tows are known. For example, an absorber comprising a tow layer of crimpable acetate fibers and a pulverized pulp layer laminated on one side of this layer, in which both layers are integrated by pressing in the thickness direction of the absorber, is known. (See Patent Document 1). According to this absorber, the diffusibility of body fluid is improved. However, since acetate fibers have a lower water absorption capacity than pulp, a large amount of pulverized pulp must be used to increase the absorption capacity of the absorber. As a result, the absorber becomes thick, and the wearing feeling of the absorbent article is lowered.

  Also, it is known that the water-absorbing core is composed of an upper layer, a lower layer and an absorbent layer located between both layers, and a fiber layer made of acetate fiber tow is disposed on the spray layer of the superabsorbent polymer as the absorbent layer. (See Patent Document 2). Acetate fibers are poor in water absorption capacity, so the amount of superabsorbent polymer affects the absorption capacity, but when a large amount of liquid is supplied to a part of the absorption core, the absorption capacity of that part is saturated, As a result of insufficient absorption of the liquid, there is a risk of liquid leakage. Although it is also conceivable to increase the absorption capacity of the absorbent core in the entire absorbent core, this increases the amount of superabsorbent polymer used, leading to an increase in cost. Moreover, in this absorptive core, the fiber layer of tow | toe and the spreading layer of a superabsorbent polymer exist separately. As a result, when the water absorbing core is deformed during wearing of the absorbent article due to the wearer's movement, the structure is easily broken.

In addition, the superabsorbent polymer bonded to the lower layer may interfere with the absorption of the liquid due to the influence of the adhesive, and the absorption efficiency per unit weight of the superabsorbent polymer is lowered, so that the absorption capacity is increased. Then, the amount of superabsorbent polymer added must be increased more than necessary. That is, in order to efficiently use the superabsorbent polymer, it is necessary to develop a loose fixing method.
Further, in the prior art, the slight absorption / swelling of the superabsorbent polymer makes the pressure applied inside the absorber very high, and the superabsorbent polymer can no longer swell. As a result, the absorber that can sufficiently contribute to absorption is only the central portion of the absorber, and high absorption performance cannot be maintained.

  It is known that a liquid-absorbing contraction member that elastically contracts by absorbing liquid is used for an absorbent article. For example, the applicant of the present invention previously disclosed in Patent Document 3 by elastically absorbing liquid on the surface on the surface layer side of the absorber and in the vicinity of the surface on the surface layer side of the absorber in the absorber. A sanitary napkin equipped with a liquid-absorbing contraction member that contracts was proposed. However, the liquid-absorbing and contracting member in this sanitary napkin does not constitute a web, and also forms a jetty having a predetermined width at the center in the width direction of the surface layer, that is, deforms the overall shape of the absorber. It is used for.

JP-A-57-160457 Special table 2004-500165 gazette JP 9-322908 A

  An object of the present invention is to provide an absorbent article that is excellent in water absorption capability and also has a good wearing feeling.

  The present invention relates to an absorbent article comprising an absorbent body containing a shrinkable fiber and a superabsorbent polymer that are shrunk by absorption of a liquid in a crimped hydrophilic long fiber web. The object is achieved by providing an absorbent article in which the body is intermittently joined to a member that does not substantially contract even when it absorbs liquid.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in water absorption capability and can provide the absorptive article with a favorable feeling of wear.

Hereinafter, the present invention will be described based on preferred embodiments with reference to the accompanying drawings.
FIG. 1 is a view showing a pants-type disposable diaper 1 (hereinafter also simply referred to as a disposable diaper 1), which is an embodiment of the absorbent article of the present invention. FIG. The expansion | deployment top view which shows the state expanded to planar shape, (b) is a schematic cross section which shows the II-II sectional view of (a).
As shown in FIGS. 1 and 2, the disposable diaper 1 includes an absorbent main body 6 and an outer layer sheet 7 disposed on the non-skin contact surface side of the back sheet 3 and fixing the absorbent main body 6. It has. The absorbent main body 6 includes a liquid-permeable top sheet 2, a liquid-impermeable or water-repellent back sheet 3, an absorbent body 4, and a second absorbent body 5, which are integrated in the thickness direction, and both ends in the longitudinal direction. The parts 6a and 6b are bonded and fixed to the outer layer sheet 7.

  The absorbent body 4 and the second absorbent body 5 have substantially the same shape in plan view, and are laminated with the absorbent body 4 positioned on the back sheet 3 side and the second absorbent body 5 positioned on the top sheet 2 side, In this state, it is arranged between the top sheet 2 and the back sheet 3. The top sheet 2 and the back sheet 3 are joined to each other at the periphery of the absorber 4 and the second absorber 5 or in the vicinity thereof.

As shown in FIG. 2, the absorbent body 4 includes a crimped hydrophilic long fiber web 41 containing shrinkable fibers 42 and a superabsorbent polymer 43 that shrink by absorption of liquid. Absorbent core consisting of long fibers of the web 41, shrinkable fiber 42 and the high absorbent polymer 43 wrapped in water-permeable fibrous sheet (not shown).

  The long fibers constituting the long fiber web 41 are hydrophilic. What is used in the present invention as a long fiber having hydrophilicity is a long fiber that is inherently hydrophilic, and inherently has no hydrophilicity, but is hydrophilic by being subjected to a hydrophilic treatment. Both of the long fibers to which is given are included. The preferred long fibers used in this embodiment are essentially non-water-absorbing long fibers that are inherently hydrophilic, with acetate long fibers being particularly preferred. Acetate is preferable because it is substantially non-water-absorbent and retains bulkiness even when wet with water. As the acetate, cellulose triacetate and cellulose diacetate are preferable.

As the long fibers constituting the long fiber web 41, crimped ones are used. The long fiber has a crimp ratio (JIS L0208) of preferably 20 to 90%, more preferably 40 to 90%, and still more preferably 50 to 80%. By forming a web from crimped long fibers, it becomes easy to stably embed and support a large amount of superabsorbent polymer in the web, even when a large amount of superabsorbent polymer is used. The extreme movement and dropout are less likely to occur. There is no particular limitation on the means for crimping the long fibers. Further, the crimp may be two-dimensional or three-dimensional. The crimp rate is defined as a percentage of the difference between the length when the long fiber is stretched and the length of the original long fiber to the length when stretched, and is calculated from the following equation.
Crimp rate = (A−B) / A × 100 (%)

  The length of the original long fiber means a length in which both ends of the long fiber are connected with a straight line when the long fiber is in a natural state. The natural state means a state in which one end of the long fiber is fixed to a horizontal plate and hung downward by its own weight. The length when the long fiber is stretched refers to the length at the minimum load when the long fiber is stretched until there is no crimp. The crimp rate of the long fibers is as described above, and the number of crimps is preferably 2 to 25, particularly 4 to 20, particularly 10 to 20 per cm.

  There is no restriction | limiting in particular in the fiber diameter of a long fiber. In general, satisfactory results are obtained by using long fibers of 1.0 to 7.8 dtex, in particular 1.7 to 5.6 dtex. In the present invention, the long fiber means a fiber having a fiber length of preferably 70 mm or more, more preferably 80 mm or more, and even more preferably 100 mm or more when the fiber length is measured by the average fiber length measurement method (Method C) of JIS L1015. Say. However, when the total length of the web to be measured is less than 100 mm, preferably 50% or more, more preferably 70% or more, more preferably 80% or more of the fibers in the web extend over the entire length of the web. In this case, it is assumed that the fibers of the web are long fibers. The long fibers used in the present invention are generally called continuous filaments. A bundle of continuous filaments oriented in one direction is generally called a tow. Therefore, the long fiber in the present invention is a concept including a continuous filament. The web in which the long fibers are oriented is a concept including a bundle of long fibers (so-called tow) as a raw material for forming the web and a tow layer of continuous filaments.

The shrinkable fiber 42 is a fiber that shrinks by absorbing liquid, and may be a short fiber or a long fiber. The length of the shrinkable fiber 42 is reduced by impregnating with a liquid such as urine, and the shrinkage rate in water at 20 ° C. is preferably 10 to 50%, preferably 20 to 40%. More preferably it is.
When the shrinkage ratio of the fibers is 10% or more, the entanglement between the fibers or the pulp fibers is sufficiently expressed, and sufficient strength is obtained. Moreover, when it is 50% or less, not only is it hardly affected by the environment, but also it is possible to prevent the absorption of the superabsorbent polymer from being inhibited by applying pressure to the superabsorbent polymer due to the shrinkage of the web.

The shrinkage ratio of the fiber is measured by the following method. That is, it is performed in accordance with the JIS L 1015-1992 chemical fiber staple test method. Specifically, referring to FIG. 8A, a rectangular thin paper a (width about 20 mm, length about 50 mm, thickness 0.2 mm) having a window b having a width of about 10 mm and a length of 20 mm, In order to take up the slack of the single fiber c, it is stretched by applying a very light tension, and both ends thereof are fixed with an adhesive d. Next, the thin paper a is cut in the width direction indicated by the dotted line e in the vicinity of the central portion in the length direction of the window b, and then immersed in water for 5 minutes. Then, after draining with filter paper, the fiber length (L ₂ ) is measured by applying tension to the extent that sagging is taken, and the shrinkage is measured by the following formula (1). FIG. 8 (b) is a diagram showing a method for measuring the melting start temperature, and shows a state in which a load is applied with a weight g. In the measurement of the shrinkage rate of the fiber, such a load is applied. Absent.

Shrinkage rate (%) = [(L ₁ −L ₂ ) / L ₁ ] × 100 (1)
L ₁ : Initial fiber length (mm)
L ₂ : Fiber length after immersion (mm)

The fact that the shrinkable fiber 42 (same as the superabsorbent polymer) is contained in the long fiber web means that at least a part thereof is present in the fiber gap of the long fiber.
From the viewpoint of shrinking the long fiber web 41, the shrinkable fiber 42 is preferably intertwined with a long fiber constituting the web 41 or partially bonded. The shrinkable fibers 42 are preferably dispersed in the longitudinal direction and / or the width direction of the absorbent body 4.
From the viewpoint of shrinking the long fiber web 41, the amount of the shrinkable fiber 42 is preferably 1 to 50% by weight, particularly 3 to 30% by weight, based on the weight of the long fiber.
When a large amount of conventional pulp is contained, the shape of the absorbent body is stabilized by strong hydrogen bonding between pulp fibers, so that even if shrink fibers are mixed, shrinkage does not easily occur. On the other hand, in the web of the present invention, since the long fibers have crimps, the long fibers are easily deformed in the length direction, and since there is no bond between the fibers, the long fibers are perpendicular to the orientation direction. It can be deformed in various directions.

It is preferable that at least a part of the shrinkable fiber is mixed in the long fiber web, the fiber constituting the long fiber web is caught, or that the shrinkable fiber is plasticized by moisture, or is entangled. Preferably more than 50%, most preferably substantially all shrinkable fibers are mixed in the web.
When some of the shrinkable fibers are mixed with the long fiber web, the rest of the shrinkable fibers are present on the outside of the web. When the shrinkable fiber layer 42 ′ is present outside the long fiber web 41 ′, it is preferably present on the back sheet side as shown in FIG. Capillary force increases due to the shrinkage of the shrinkable fiber layer and the distance between fibers increases, so that the liquid drawability increases, so that the liquid draw force of the absorbent body is strengthened by placing it on the back sheet side. Can do. On the other hand, as shown in FIG. 7B, when the shrinkable fiber layer 42 ′ is provided on the top sheet side, a liquid residue is generated in the layer, and the dryness of the absorbent article is insufficient.
In the absorbent body shown in FIG. 7, the long fiber web 41 ′ and the long fiber web 41 ′ are formed on the long fiber web 41 ′ in the vicinity of the surface of the long fiber web 41 ′. A region 45 in which the shrinkable fibers are mixed is formed. Further, in the absorbent body shown in FIG. 7 (a), the shrinkable fibers that shrink due to the absorption of the liquid are arranged biased toward the back sheet side in the long fiber web 41 'and are close to the web. It is arranged on the back sheet side from the web.

  As the shrinkable fiber 42, those that shrink by absorption of liquid can be used without particular limitation. For example, fibers made of various materials listed in paragraph [0020] of Patent Document 3 can be used. Preferred materials are polyvinyl alcohol (PVA), polyvinyl pyrrolidone, pullulan, carboxymethyl cellulose (CMC), carboxyethyl cellulose (CEC), hydroxypropyl cellulose, starch, polyethylene glycol (PEG), polyethylene oxide (PEO), polysaccharides, polyacetic acid A fiber made of vinyl, polyacrylic acid, a certain shape memory material or the like is preferable, and a polyvinyl alcohol fiber is particularly preferable. Polyvinyl alcohol may be modified with maleic acid or itaconic acid. Further, each polymer material such as polyvinyl alcohol described above is not limited to the fibrous form, and may be incorporated into the absorbent body in the form of a thin piece such as a sheet form or a ribbon form.

  In order to impart the above-described shrinkage to these fibers, for example, polyvinyl alcohol fibers can be controlled by changing the molecular weight, saponification degree, crystallinity, etc. Fibers are commercially available under trade names such as Kuraray Vinylon, Cremona [all manufactured by Kuraray Co., Ltd.], Unitika Vinylon [manufactured by Unitika Ltd.], Sorbron, Nichibilon [all manufactured by Nichibi Co., Ltd.], etc. ing.

  The shrinkable fiber is generally a fiber having a high affinity for water, but it exhibits shrinkage and does not cause clogging of the absorbent body, so its solubility in water is limited. The dissolution start temperature in water is preferably more than 50 ° C, more preferably 50 to 90 ° C. A fiber having a dissolution start temperature in water of less than 50 ° C. is not preferable because it may dissolve when the absorbent body absorbs the body fluid.

As shown in FIG. 8 (a), this water dissolution starting temperature measurement method is a rectangular thin paper a having a width b of about 10 mm and a length of 20 mm (width about 20 mm, length about 50 mm, thickness 0.2 mm), the single fiber c is stretched with a very light tension in order to take up its slack, and both ends thereof are fixed with an adhesive d.
Next, after the thin paper a is cut in the width direction indicated by the dotted line e in the vicinity of the central portion of the window b in the length direction, a load of 1/20 cN of the display denier is applied to the lower side of the fiber . As shown in FIG. 8 (b), a sample is set in the water tank f, the water temperature is gradually raised, and the lowest temperature at which the fiber can not withstand the weight due to the weight g and is cut is called the melting start temperature.

The shrinkable fiber 42 preferably has a fineness of 0.1 to 10 dtex, particularly 0.5 to 5 dtex, from the viewpoint of carrying a superabsorbent polymer.
Further, the shrinkable fibers 42 preferably have an average fiber length of 10 mm or more, particularly 15 mm or more from the viewpoint that the shrinkage rate of the web can be increased. Since the average fiber length of the shrinkable fibers 42 may be long fibers as described above, the average fiber length is not particularly limited, and may be a length over the entire length in the longitudinal direction or the entire length in the width direction of the absorbent body 4.

The shrinkable fiber 42 may be a crimped hydrophilic long fiber. That is, some of the long fibers constituting the above-described long fiber web may be shrinkable fibers. When all the long fibers are made of shrinkable fibers, the contractile force can be transmitted to the entire web by utilizing the liquid diffusibility inherent in the long fibers, and the superabsorbent polymer can be used effectively. This is suitable for older babies with large excretion and disposable diapers for adults.
On the other hand, when a part is made of shrinkable fibers and mixed with non-shrinkable fibers, shrinkage is performed only on the portions where the shrinkable fibers are present, so that the drawability of the liquid at the shrinkage portion is improved. It is excellent in that the wet region and the dry region can be separated.

  The superabsorbent polymer 43 is preferably embedded and supported in a long fiber web 41. The buried support refers to a state in which the superabsorbent polymer enters the space formed by the crimped long fibers, and the polymer is not easily moved or dropped even by vigorous movement of the wearer. . At this time, the long fibers are entangled or caught in the superabsorbent polymer, or the superabsorbent polymer is attached to the long fiber due to its own stickiness. The space formed by the long fibers is easily deformed even when stress is applied from the outside, and the entire long fibers can absorb the stress, thereby preventing the space from being destroyed.

  The superabsorbent polymer 43 may be uniformly dispersed in the thickness direction of the web 41, or may be present in a biased position in a region extending from the central portion to the lower portion of the web 41 in the thickness direction. Further, the web 41 may be biased to a portion extending from the center in the thickness direction to the upper portion.

  Since the long fibers constituting the web 41 have crimps, the long fibers have a large number of spaces capable of holding particles. The superabsorbent polymer is retained in the space. As a result, even if a large amount of superabsorbent polymer is sprayed, the extreme movement or dropout is less likely to occur. Moreover, even if a wearer performs intense operation | movement, the structure of the absorber 4 becomes difficult to be destroyed. Depending on the superabsorbent polymer used, the crimp rate and the amount of long fibers used are adjusted as appropriate. Even in the conventional absorbent body, if the amount of the fiber material is increased, a large amount of the superabsorbent polymer can be retained, but in this case, the basis weight and thickness of the absorbent body are increased. On the other hand, in this embodiment, it is easy to make the amount of the superabsorbent polymer relatively large with respect to the amount of the fiber material. Specifically, when viewed as a whole of the absorbent body 4, the basis weight of the superabsorbent polymer is preferably at least the basis weight of the long fibers, more preferably at least twice, and even more preferably at least three times. Thereby, the absorber 4 and, in turn, the absorbent article can be reduced in thickness and weight. The upper limit value of the ratio of the basis weight of the superabsorbent polymer to the basis weight of the long fiber is determined from the viewpoint of extreme movement of the superabsorbent polymer and prevention of falling off. Although depending on the degree of crimp of the long fibers, if the upper limit is about 10 times, the superabsorbent polymer is unlikely to move or drop out even if the wearer performs a violent operation.

  The following method can be used as an evaluation method to the extent that the superabsorbent polymer is buried and supported. The central part in the longitudinal direction of the web produced to 100 mm × 200 mm is cut to obtain a 100 mm × 100 mm test piece. This cut surface is directly below, and vibration is applied to the left and right 20 times at a speed of once / second with an amplitude of 5 cm. Measure the weight of polymer dropped from the cut surface. When the weight of the dropped superabsorbent polymer is 25 wt% or less, particularly 20 wt% or less, especially 10 wt% or less, based on the total amount of the superabsorbent polymer present in the test piece, It can be said that this is a state in which the extreme movement and dropout of the functional polymer are difficult to occur.

  The following evaluation method can also be performed on the test piece subjected to the drop evaluation test. 50 g of physiological saline (0.9% saline) is evenly sprayed on the test piece subjected to the drop-off evaluation test, and the way the test piece swells is visually observed. When the variation in the thickness of the test piece is within 2 times, it can be said that it is difficult for the superabsorbent polymer to move or drop off.

  In each of the evaluation methods described above, when the web is viewed in the horizontal direction, the test piece is sampled from a region where the superabsorbent polymer is dispersed with the same basis weight.

  In the absorbent body 4, the long fibers constituting the web 41 are oriented in one direction in the plane direction of the absorbent body 4. When the liquid is absorbed in the absorbent core 41 due to the orientation of the long fibers in one direction, the liquid preferentially diffuses in the orientation direction of the long fibers. That is, it diffuses preferentially in the planar direction of the absorber. Conversely, diffusion in the direction perpendicular to the orientation direction of the long fibers is suppressed. In the diaper 1 of the present embodiment, since the long fibers are oriented in the longitudinal direction of the absorbent article, partial shrinkage of the long fiber web is likely to occur in the longitudinal direction of the absorbent article. On the other hand, when oriented in the width direction of the absorbent article, partial shrinkage of the long fiber web tends to occur in the width direction of the absorbent article.

  The degree of orientation of the long fibers is preferably 1.2 or more, particularly 1.4 or more in terms of the degree of orientation. In this embodiment, the degree of orientation is measured using a Microwave molecular orientation analyzer MOA-2001A manufactured by KANZAKI. The sample size is 100 mm in the longitudinal direction and 50 mm in width, and the average value of three points is the degree of orientation. When the sample size is less than this size, measurement is performed by arranging a plurality of samples so as not to overlap each other.

  Next, the manufacturing method of the absorber 4 of this embodiment is demonstrated, referring FIG. FIG. 3 shows an apparatus suitably used for manufacturing the absorber 4. The manufacturing apparatus includes a fiber opening means 20 for sequentially opening the long fibers 10 during the conveyance thereof.

  The opening means 20 includes opening machines (banding jets) 21, 22, and 23 that sequentially open the long fibers 10 being conveyed. Further, the opening means 20 includes a guide 24 for lowering the long fiber 10 once sent upward between the opening machines 21 and 22, and a feeding roll 25 between the opening machines 22 and 23. And a blooming roll 26.

The spreaders 21, 22, and 23 are devices that spread air by blowing air to open the long fibers 10 being conveyed. The feeding roll 25 includes a pair of rolls that nip the long fibers 10 opened by the spreader 22 and feed them at a predetermined speed. The blooming roll 26 is provided with a roll 260 and an anvil roll 261 in which a large number of disks are incorporated at predetermined intervals around an axis, and the long fiber 10 in a state where tension is applied is spread. A polymer supply means 27 is provided at a position downstream of the spreader 23. The polymer supply means 27 is a device that uniformly spreads a predetermined amount of the superabsorbent polymer 43 on the long fibers after being sown by the blooming roll 26.
The manufacturing apparatus includes a shrinkable fiber supply device (not shown). The feeding device transports the shrinkable fiber web 30 manufactured by the card machine using a known transport mechanism, and is opened between the feeding roll 25 and the blooming roll 26 by the spreader 22. Combine with fiber 10.

  In the manufacturing method of the absorber 4 using the manufacturing apparatus having the above configuration, the long fibers 10 are conveyed in a state where a predetermined tension is applied thereto. As described above, since the long fibers 10 have crimps, when the tension is applied, the long fibers 10 are easily stretched in the longitudinal direction. Under this state, the long fibers 10 are opened by the spreaders 21, 22, and 23 of the opening means 20 so as to widen the width. By using a plurality of fiber spreaders, the width of the long fiber 10 can be expanded stepwise without difficulty.

  The long fibers 10 are wound by a blooming roll 26 positioned between the spreaders 22 and 23, and the fibers 42 constituting the shrinkable fiber web 30 are dispersed and pushed into the fibers of the long fibers 10.

The superabsorbent polymer 43 is sprayed on the long fibers 10 including the shrinkable fibers. At the time of spreading, the tension for transporting the long fibers 10 is weakened and the stretched state of the long fibers 10 is released. As a result, the long fibers 10 return to the crimped state, and the superabsorbent polymer 43 is dispersed under the state. The long fibers in a crimped state have voids that can accommodate the superabsorbent polymer 43 between the fibers. The superabsorbent polymer is buried and supported in the voids. On the other hand, in a state where the long fiber 10 is stretched and stretched, there is not enough space to accommodate the superabsorbent polymer 43, so that the superabsorbent polymer 43 is successfully embedded and supported. It is not easy. Simultaneously with the dispersion of the superabsorbent polymer 43, it is effective to suck the polymer 43 from the surface opposite to the surface to which the polymer 43 is dispersed to promote the buried support of the polymer 43. By appropriately adjusting the degree of suction, the distribution of the polymer 43 in the web thickness direction can be changed.
The dispersed superabsorbent polymer is held in a space formed by crimped long fibers. After the superabsorbent polymer is sprayed, the web is compressed with a roll, a belt, or the like, so that the superabsorbent polymer is embedded in the web. In this way, the superabsorbent polymer is buried and supported in the web.

  Another method is to spread a superabsorbent polymer on the central region in the width direction of a wide long fiber web that has developed crimpability, and then laminate a shrinkable fiber web 30 on the superabsorbent polymer. Thereafter, the long fiber web may be wound up to wrap the web 30 of superabsorbent polymer and shrinkable fibers. In this case, the order of spreading the superabsorbent polymer and laminating the web 30 of shrinkable fibers may be interchanged.

  Prior to spraying the superabsorbent polymer, various adhesives such as hot melt adhesive are applied to the long fiber web by contact method such as roll coater method and screen printing method, and non-contact method such as spray method. However, the application of such an adhesive tends to scatter the adhesive and inhibit the shrinkage of the long fibers by the shrinkable fibers. The aspect currently adhere | attached by the adhesion point is mentioned. For example, a method of applying a hot melt pressure-sensitive adhesive by a spray method may be used as the dotted adhesive. Examples of the spray method include a slot spray method, a curtain spray method, a melt blown method, and a spiral spray method.

  Further, prior to the dispersion of the superabsorbent polymer, a fiber sheet (not shown) is joined to the lower surface side of the long fiber web, and after the polymer is dispersed, the fiber sheet extending from the lower surface of the web, The fiber sheet is covered with a lower surface, both side portions, and an upper surface of the web by being bent toward the upper surface side of the web by a bending guide (not shown).

  The fiber sheet is preferably made of a material that has sufficient strength to prevent the superabsorbent polymer from falling off and that does not hinder the permeation of excreted liquid. Moreover, the fiber sheet is comprised from the tissue and nonwoven fabric conventionally used widely. The nonwoven fabric may be subjected to a hydrophilic treatment or a hole opening treatment as necessary. Further, a slit may be formed. As the non-woven fabric, for example, a fiber using a thermoplastic resin such as polyethylene, polypropylene, or polyethylene terephthalate alone or a composite fiber using a plurality of these resins as a raw material can be used. Examples thereof include a thermal bond nonwoven fabric, a spunbond nonwoven fabric, a spunbond-meltblown-spunbond nonwoven fabric, a spunbond-meltblown-meltblown-spunbond nonwoven fabric, a needle punched nonwoven fabric, a spunlace nonwoven fabric, and an airlaid nonwoven fabric.

By covering the web 41 with a fiber sheet, the extreme movement and dropping off of the superabsorbent polymer 43 contained in the web can be effectively prevented. Furthermore, since the handling property as the absorber 4 as a whole becomes good, it can be easily transported alone. Moreover, since it becomes possible to easily cut or cut into a desired shape, it is easy to manufacture an absorbent body according to the shape of the absorbent article.
The surface of the fiber sheet facing the web 41 of the long fiber containing the shrinkable fiber and the superabsorbent polymer is coated with various adhesives such as a hot melt pressure-sensitive adhesive by a spray method. Bonded by many small bonding points. Examples of the spray method include a slot spray method, a curtain spray method, a melt blown method, and a spiral spray method.

  The absorbent body 4 in the diaper 1 of the present embodiment is intermittently joined to the second absorbent body 5 with an adhesive such as a hot melt adhesive. The 2nd absorber 5 contains the web of the crimped hydrophilic long fiber, and does not contain the shrinkable fiber and superabsorbent polymer which shrink | contract by absorption of a liquid. The second absorbent body 5 in the present embodiment has the same configuration as the absorbent body 4 except that it does not contain shrinkable fibers and superabsorbent polymers, and joins the web made of shrinkable fibers to the long fibers. In addition, the absorbent body 4 can be produced in the same manner as described above, except that the superabsorbent polymer is not sprayed and coated with the covering sheet.

In the diaper 1 of this embodiment, the absorber 4 and the second absorber 5 are joined intermittently in the diaper longitudinal direction. The joint portion 44 between the absorbent body 4 and the second absorbent body 5 has a narrow strip shape and is intermittently formed in the diaper longitudinal direction, but is continuous in the diaper width direction. The joining portion 44 extends over substantially the entire length in the width direction of the absorber 4. The joint portion 44 between the absorbent body 4 and the second absorbent body 5 is preferably a distance L1 between adjacent joint portions (see FIG. 2) of 10 mm or more from the viewpoint of expressing the shrinkability of the shrinkable fiber, It is preferable that it is 100 mm or less from the viewpoint of integrating the absorbent body with other diaper constituent members in order to provide a sense of incongruity during wearing and stabilization of absorption performance. From such a point, the distance L1 between adjacent joints is more preferably 10 to 100 mm.
Moreover, as for the width L2 (refer FIG. 2) of each junction part 44, it is more preferable that the width L2 of each junction part 44 is 0.5-5 mm from the point of coexistence of adhesiveness and contractility.

  In the diaper 1 of the present embodiment, the shrinkable fibers are also generally oriented in the longitudinal direction of the absorbent article [vertical direction in FIG. 1 (a)].

The formation material of each part in the diaper 1 of this embodiment is demonstrated.
As the top sheet 2, the back sheet 3, and the outer layer sheet 7, materials usually used in the technical field can be used without any particular limitation. For example, as the top sheet, a liquid permeable sheet such as various non-woven fabrics or apertured films subjected to a hydrophilic treatment can be used. The back sheet 3 may be a liquid permeable or water repellent sheet such as a thermoplastic resin film or a laminate of the film and a nonwoven fabric.

According to the disposable diaper 1 of the present embodiment, for example, when urine is supplied to the portion indicated by A1 in FIG. 2 of the top sheet 2 and the absorber 4 located below absorbs urine, the urine is absorbed. The shrinkable fibers in the part are shrunk by liquid absorption, whereby the crimped long fibers gather together with the superabsorbent polymer in the part, while the other parts are stretched by being stretched from the crimped state. This increases the density of the superabsorbent polymer in the portion that has absorbed the urine and enhances the absorption capacity of that portion. On the other hand, the density of the long fibers and the superabsorbent polymer is reduced outside the portion that has absorbed urine. The ability to gather and absorb that part is similarly enhanced. In the case where a large amount of urine is supplied to the portion indicated by A2 in FIG. 2 instead of the portion indicated by A1 in FIG. 2, similarly, due to the shrinkage of the shrinkable fibers, the long fibers and the superabsorbent polymer of the portion Density increases and absorption capacity is enhanced.
By such an action, even if a large amount of liquid is supplied to the same part of the collector 4, wetback and liquid leakage due to saturation of the absorption capacity are unlikely to occur.

Further, even if the density of the long fibers and the superabsorbent polymer is partially rough due to the shrinkage of the shrinkable fibers, the strain is relaxed inside the second absorbent body, and the surface of the absorbent body 4 is substantially flat. Is maintained. Moreover, since the 2nd absorber is rich in a softness | flexibility, an unevenness | corrugation does not arise in the skin contact surface of a diaper, and a discomfort and a leak are hard to produce.
The intermittent joint portion 44 between the absorbent body 4 and the second absorbent body 5 is important in order to generate a portion having a high density of long fibers and superabsorbent polymer inside the absorbent body 4. In addition, in the diaper 1 of this embodiment, when the absorber 4 and the 2nd absorber 5 are not joined intermittently, shrinkage will be inhibited by an adhesive agent.

  In the diaper 1 of the present embodiment, the object to which the absorbent body 4 is intermittently joined includes a crimped hydrophilic long fiber web, and substantially includes shrinkable fibers that contract by absorption of liquid. There is no second absorber. Even if partial contraction occurs in the second absorbent body having such a configuration, it is easy to maintain a flat state as a whole. The second absorbent body 5 may be one in which a superabsorbent polymer is embedded and supported in a long fiber web.

  Moreover, in the diaper 1 of the present embodiment, the absorbent main body 6 is joined to the outer layer sheet 7 only at the longitudinal ends 6a and 6b, and is not joined to the outer layer sheet 7 in the vicinity of the urination point. There are also advantages that the contraction is less disturbed and that there is less discomfort at the crotch.

  Hereinafter, the disposable diaper of other embodiment of this invention is demonstrated. About the point which is not demonstrated especially regarding these embodiment, the description regarding the diaper 1 mentioned previously is applied suitably. Moreover, in FIG. 4, the same code | symbol is attached | subjected to the same member as the disposable diaper 1 shown in FIG.1 and FIG.2.

In the disposable diaper 1A shown in FIG. 4 (a), the absorbent body 4 is intermittently joined to the top sheet 2. In the disposable diaper 1B shown in FIG. 4 (b), the absorbent body 4 is The back sheet 3 is intermittently joined.
In each of these embodiments, the top sheet 2 and the back sheet 3 are made of a material that does not substantially contract even when the liquid is absorbed. In these disposable diapers 1A and 1B, the absorber 4 is included in these materials. Since it is joined intermittently, the same effect as the disposable diaper 1 mentioned above is produced.

The present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the spirit of the present invention.
For example, in the diaper of each embodiment described above, the long fibers in the absorbent body are oriented in the longitudinal direction of the absorbent article (the left-right direction in FIG. 1A), and the absorbent body 4 and the second absorbent body 5 Are formed intermittently in the longitudinal direction of the absorbent article (continuously in the longitudinal direction). However, as in the disposable diaper 1C shown in FIG. The absorbent body 4 oriented in the width direction of the article (vertical direction in FIG. 5) and containing shrinkable fibers, the second absorbent body 5, the top sheet 2, the back sheet 3, and the like are not substantially shrunk even when absorbed. The joint portion 44 with the member can also be formed intermittently (continuously in the width direction) in the width direction of the absorbent article. Moreover, it is good also considering the orientation direction of the long fiber in the absorber 4 and the direction where the junction part 44 is extended as the same direction (parallel). Moreover, the joining part 44 may be formed to be inclined so as to have a predetermined angle with respect to the longitudinal direction or the width direction of the absorbent article, and the joining part 44 may be formed in a lattice shape.

The absorbent article of the present invention may be an unfolded disposable diaper as shown in FIG. A disposable diaper 1D shown in FIG. 6 is an unfolded disposable diaper in which a fastening tape 8 provided on both left and right sides of one end in the longitudinal direction is attached to a landing tape 81 provided on the other end in the longitudinal direction. .
Furthermore, the absorbent article in the present invention may be an incontinence pad, a sanitary napkin, a panty liner, etc., in addition to a pants-type or unfolded disposable diaper.

  FIG. 9 is a schematic cross-sectional view of an absorbent body configured by laminating a crimped hydrophilic long fiber web 41 ′ and a shrinkable fiber web 42 ′. In the absorbent body shown in FIG. 9, a superabsorbent polymer is embedded and supported on a long fiber web 41 ', but the web 41' does not contain shrinkable fibers. In the case of this absorbent body, the web 41 ′ and the web 42 ′ are integrated by wrapping them in a fiber sheet such as tissue paper. In this way, a crimped hydrophilic long fiber web 41 'containing a superabsorbent polymer is placed close to the shrinkable fiber web, and the both are integrated by some means. Even in the case where such an absorbent is used, an absorbent article having excellent water absorption ability and good wearing feeling can be obtained by intermittently joining it to a member that does not substantially contract even when absorbing liquid. Obtainable. FIG. 9 shows a state in which a long fiber web 41 ′ is arranged on the back sheet (not shown) side and a web 42 ′ made of shrinkable fibers is arranged on the top sheet (not shown) side. Both webs can be turned upside down.

FIG. 1 is a diagram showing a pants-type disposable diaper that is an embodiment of the absorbent article of the present invention, and (a) is a developed plan view showing a state in which the diaper is developed and expanded in a planar shape, (b) ) Is a schematic cross-sectional view showing a cross section taken along line II-II in (a). FIG. 2 is a schematic cross-sectional view showing an enlarged part of a cross section taken along line II in the disposable diaper of FIG. FIG. 3 is a perspective view illustrating an outline of an example of an absorbent body manufacturing apparatus. FIG. 4 is a diagram showing a pants-type disposable diaper according to another embodiment of the present invention, and is a schematic cross-sectional view corresponding to FIG. It is a figure which shows other embodiment of this invention, and is an expansion | deployment top view equivalent to Fig.1 (a). It is a top view which shows the surface by the side of the top sheet of the expansion | deployment type diaper which is further another embodiment of this invention. It is a figure which shows the example of the absorber which can be used for this invention. FIG. 8A is a diagram for explaining a method for measuring the shrinkage rate of the shrinkable fiber, and FIG. 8B is an explanatory diagram for explaining a method for measuring the melting start temperature of the shrinkable fiber. It is a figure explaining the absorber of the other structure which can show | play the effect equivalent to this invention, and is sectional drawing of the thickness direction.

Explanation of symbols

1 disposable diaper (absorbent article)
2 Top sheet 3 Back sheet 4 Absorbent body 41 Long fiber web 42 Shrinkable fiber 43 Superabsorbent polymer 5 Second absorbent body

Claims (6)

An absorbent article comprising an absorbent body having a crimped hydrophilic long fiber web, a superabsorbent polymer contained in the web , and a shrinkable fiber that contracts by absorbing liquid,
The absorber is intermittently joined to a member that does not substantially contract even when absorbing liquid ,
In the shrinkable fibers, some of the shrinkable fibers are present in the fiber gaps of the long fibers in the long fiber web, and the other part of the shrinkable fibers are adjacent to one side of the long fiber web. An absorbent article constituting a layer of shrinkable fibers . The member that does not substantially contract when absorbing liquid is the top sheet and / or the back sheet of the absorbent article,
The absorber, the absorbent article according to claim 1, wherein is intermittently joined to the topsheet and / or backsheet. The absorbent article according to claim 1 or 2, wherein the crimp rate of the long fibers is 20 to 90%. The shrinkable fiber layer is formed from a part of a web made of a shrinkable fiber that is laminated on the long fiber web and contracts by absorbing liquid, and the shrinkable fiber in the long fiber web The area | region where the long fiber which comprises the web of this long fiber, and the shrinkable fiber which comprises the web which consists of a shrinkable fiber are mixed is formed in the surface vicinity of the layer side of any one of Claims 1-3 The absorbent article of Claim 1. In addition to the long fiber web and the shrinkable fiber layer, the absorber has a fiber sheet that wraps the long fiber web and the shrinkable fiber layer. The absorbent article according to any one of claims 1 to 4 , wherein the shrinkable fiber layer is disposed on the top sheet side and the back sheet side . An absorbent article comprising an absorbent body having a crimped hydrophilic long fiber web, a superabsorbent polymer contained in the web, and a shrinkable fiber that contracts by absorbing liquid,
The absorber is intermittently joined to a member that does not substantially contract even when absorbing liquid,
The shrinkable fibers are not contained in the long fiber web, and are contained in a web made of shrinkable fibers different from the web.
The long fiber web and the shrinkable fiber web are wrapped and integrated in a fiber sheet, the long fiber web is on the top sheet side, and the shrinkable fiber web is on the back sheet side. Absorbent articles that are arranged.

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