KR20010100981A - Absorbent core for use in a sanitary absorbent article and method for manufacturing - Google Patents

Abstract

The present invention relates to a physiological absorbent article comprising an absorbent sheet comprising a "wet laid" paper and a method of making the same. These wet integrated papers are glued and covered with a super absorbent material and wrap the product's absorbent core.

Description

Absorbent core for use in a sanitary absorbent article and method for manufacturing

The present invention is an absorbent for use in disposable physiological absorbent products, such as panty liners, sanitary napkins and adult incontinence devices designed to absorb and contain menses and other vaginal secretions designed and manufactured to be worn on the crotch portion of wearer's underwear. It's about the core.

Physiological absorbent products are used to absorb and receive urine exudates, in particular in the case of menstrual discharge, menstrual blood and also urinary incontinence. In order to improve comfort, the product does not use a thick layer of absorbent material.

Physiological absorbent products known in the art are typically made of absorbent materials, which are substantially flat and elongated in shape and surrounded by an upper permeable layer in contact with the user's body and a lower impermeable layer moving with the user's panties. It consists of a body.

The upper permeable layer is intended to be in contact with the pelvic area of the user and thus is made of a material that is as comfortable and non-irritating as possible. According to the state of the art, the layer can be a perforated plastic film, porous or crosslinked foam and made of natural fibers (wood or cotton fibers), artificial fibers (polyester or polypropylene) or even synthetic or natural fibers. It may be a sheet of a woven or nonwoven substrate with composite fibers. The upper layer above may be a hydrophobic substrate and tends to remain dry.

The lower impermeable layer, on the other hand, is optionally made of polyethylene sheet and has a function of preventing the fluid absorbed and retained in the absorbent body from leaking to the user's clothes or skin. The bottom layer can be vapor permeable and in this case are made of a nonwoven substrate provided with small voids or impermeable to liquid.

The body made of absorbent material comprises two elements: a transfer layer and an absorbent core. The absorbent core then consists of an absorbent sheet surrounded by a super absorbent material.

Typically, the substrate used to make the absorbent sheet is a paper known as air-laid. This kind of paper is made of cellulose and provides a non-oriented fiber structure to provide good liquid dispersion. Some types of nonwovens are still used in place of "air accumulation" paper.

Superabsorbents are known in the art and are generally provided as powder in the form of hygroscopic granules. The granules are fixed to the absorbent sheet and they have the function of keeping the liquid absorbed in the absorbent core of the physiological absorbent product.

The substrate used to make the absorbent sheet of the absorbent core is particularly important for the absorbent to have good efficiency because the sheet must be able to uniformly absorb, disperse or deliver the liquid in the super absorbent material.

A substrate known in the art that provides features similar to those set forth above is described in EP0146190. The above substrate has multiple absorbent layers which surround the super absorbent material to form a structure which undergoes the embossing process.

One of the problems found in the manufacture of physiological absorbent products is that the type of air-aggregated paper is expensive, raising the final price for each absorbent material.

It is an object of the present invention to provide a physiological absorbent product that uses "wet laid" paper in the manufacture of an absorbent core, ie replaces the "air accumulation" paper currently used to make absorbent cores. To provide. This object can be achieved through a physiological absorbent article comprising an upper layer permeable to a liquid, an impermeable lower layer to a liquid, a delivery layer and an absorbent core, wherein the absorbent core is attached to the absorbent sheet and the sheet inner surface. A sheet comprising superabsorbent material and having a longitudinal axis side folded over the inner surface is made using wet integrated paper.

It is another object of the present invention to produce absorbent cores using wet integrated paper instead of air integrated paper. This object can be achieved through an absorbent core, in particular an absorbent core for a physiological absorbent product, wherein the absorbent core comprises an absorbent sheet and a super absorbent material attached to the inner surface of the sheet, the sheet being folded over its inner surface. Paper has a longitudinal side and is made of wet integrated paper.

Still another object of the present invention is to provide a method of making an absorbent core using "wet integrated" paper instead of the "air integrated" paper typically used to make absorbent cores. This object is achieved through a process for producing an absorbent core, in particular an absorbent core for a physiological absorbent article, wherein the article comprises an upper layer permeable to the liquid and an lower layer impermeable to the liquid, Spraying the adhesive onto a "wet integrated" paper sheet suitable for making the absorbent core, applying the superabsorbent material onto the adhesive material, and folding the paper sheet to form the absorbent core, embossing and perforating the absorbent core.

1 is a perspective view of a top surface of a physiological absorbent product according to the present invention.

2 is a cross-sectional view of the product found in FIG. 1.

3 is a perspective view of the underside of an absorbent core according to the invention.

FIG. 4 is a schematic diagram of an embossing type used to make the absorbent core shown in FIG. 3.

5 is a top perspective view of an absorbent sheet according to the present invention.

6 is an enlarged view of the absorption sheet of FIG. 5.

While this specification concludes with the claims particularly pointed out and specifically claimed by the heart of the invention, it is believed that the invention is more readily understood from the following detailed description taken in conjunction with the drawings, wherein the reference numerals in the drawings constitute a substantial construction. Specifies the component.

As is already known in the art, a physiological absorbent product is a lower impermeable layer that can work with the top layer 2 and panties (not shown) permeable to a liquid suitable for intimate contact with the user's pelvic area. A body 5 of absorbent material in a substantially flat shape, surrounded by (3).

It is contemplated that the flexible side tabs 4 which extend laterally on or separate from the upper layer 2 and the lower layer 3, or one of them, are associated with the absorbent material 1. The underside of each of these tabs 4 still has an adhesive site (not shown) to be secured to the crotch portion of the user's panties. Another adhesive site (also not shown) can be considered in the longitudinal center portion of the lower layer 3 of the absorbent material 1.

As described in FIG. 2, the absorbent body 5 (defined by the dashed area) is a transfer layer 7 adjacent to the absorbent core 8, which consists of an absorbent sheet 9 having an inner surface covered with a super absorbent material 10. It consists of

According to the invention, the absorbent sheet 9 of the absorbent core 8 is made of "wet integrated" paper instead of the "air integrated" paper of conventional physiological absorbent articles.

As is known in the art, "wet accumulation" or "moisture accumulation" papers or even tissue papers adhere cellulose onto a permeable screen to provide a paper layer and compress it to obtain a good absorbent paper.

However, it is not currently possible to simply change the "air accumulation" paper used in the manufacture of the absorbent sheet 9 into a "wet accumulation" type paper, because a series of wet integration papers must be solved according to the present invention. This is due to a technical problem.

For example, the problem found in "wet integrated" type paper when used in the manufacture of the absorbent sheet 9 is that the absorption and dispersal of the liquid by the absorbent core 8 to a certain degree or less is impeded to the absorbent core 8. It is derived from the fact that it consists of oriented fibers that increase the absorption time of the liquid thereby increasing the likelihood of reaching the saturation point in the core 8. Thus, leakage may occur in physiological absorbent products.

Another problem found in "wet integrated" type paper is that its surface provides some impermeability by the manufacturing process to limit its application in making the absorbent sheet 9.

Still, a further problem with wet-integrated papers is that these substrates are somewhat inflexible, which renders the user of the absorbent material 1 uncomfortable, making it inappropriate to use the paper in a physiological absorbent product 1 without proper treatment. .

Thus, manufacturing the product 1, which examines the steps of embossing and perforating the absorbent core 8 so that this kind of paper can be used to solve the problems resulting from using the above-mentioned "wet integrated" paper. I was considering how to do it.

As shown in Fig. 3, the absorbent sheet 9 is divided into three parts: the central part A and the two faces B. The central part A has a longitudinal central band that is approximately one-half of the width of the sheet 9; Include. The side part B is formed by the longitudinal axis side of the sheet 9.

In order to manufacture the absorbent core 8, one may consider initially spraying an adhesive onto the inner surface of the absorbent sheet 9. The method of applying the adhesive on the absorbent sheet 9 is also known as "spray hot melt" using a thermoplastic adhesive.

Preferably, the amount of adhesive applied on the inner surface of the absorbent sheet 9 is in the range of 0.01 to 1.00 g per 100 cm ² , most preferably 0.30 g to 0.40 g per 100 cm ² . When an adhesive layer is applied, the layer of superabsorbent material 10 known in the prior art is in granular form and is preferably distributed relatively uniformly on the adhesive layer.

The selection of specific superabsorbents for a product has been found to play an important role in fluid handling performance. Preferred superabsorbents have an absorbency under load (AUL) value that absorbs at least about 24 ml of saline per gram of superabsorbent. Tests for AUL are described in US Pat. No. 5,147,343, issued to September 15, 1992 to Kelenberger. High numerical AUL values reduce the potential for superabsorbents to become gel blocks, especially in structures with wet integrated paper laminates, which limits the amount of fibrous substrate useful for aiding fluid dispersion wicking. U. S. Patent 5,562, 646 (Goldman, dated Oct. 8, 1996) describes additional properties that allow the superabsorbent to function well in the structure. These properties are porosity, performance under pressure, and saline fluid inflow conductivity. The relatively high values of these properties allow the superabsorbent layer to acquire and deliver fluids at the speed required for good performance without any contribution from the wet integrated substrate. do. Preferred values are porosity greater than 0.15, performance under pressure of at least 23 g / g under a limit pressure of 0.7 psi and saline inflow conductivity of at least about 30 × 10 ⁻⁷ cm ³ sec / g.

In a preferred embodiment, after applying the super absorbent material, the absorbent sheet 9 is folded so that both side portions B cover the layer of the super absorbent material 10 attached to the inner surface and are protected by the absorbent sheet 9. Cover the central portion A to form a layer.

Preferably, the folded portion of the absorbent sheet 9 shown in the profile is substantially C-shaped (see FIG. 3). Another aspect may assume different profiles comprising or even substantially equivalent G-shaped profiles. As shown in Fig. 3, the ends of the side portion B meet when they are folded and are fixed from one end to another, since the adhesive itself retains the portion B covered over the portion A.

Preferably, the face of the core 8, on which the side B of the absorbent sheet 9 is located, is positioned to face the face of the impermeable lower layer 3 of the absorbent material 1.

In a preferred embodiment, the absorbent core 8 is embossed and perforated once the absorbent sheet 9 is folded.

Embossing of the substrate is a known technique and can be applied in a balanced or truncated form or another corresponding form. The technique increases the contact surface of the absorbent sheet 9 and thus increases the absorbent power of the absorbent core 8.

Embossing is carried out through two embossing rolls, the upper roll and the lower roll, each of which has an embossed surface formed by teeth of a particular specification. The embossment mentioned is imprinted on the substrate to emboss the substrate, i.e. in the case of the invention, the emboss is imprinted on the absorbent core 8 during embossing. As is known in the art, the measurement that must be taken into account during the embossing process is the so-called depth band. These measurements indicate to what extent the outer edges of the teeth or embossed edges of the roll depress the outermost edges of the embossed teeth of another roll.

The type of embossing which is preferably applied to the absorbent core is known in the art as "side x side centered". In this kind of embossing, as shown in FIG. 4, the upper roll allows the compartment 40 to be positioned among the three compartments 41 formed by the lower roll. Preferably, the depth band used in the present invention is 0.030 to 0.040 inch (0.762 to 1.016 mm) and most preferably 0.035 inch (0.889 mm). Preferably the embossing speed is 30 feet per minute (9.144 meters per minute).

As explained in FIGS. 5 and 6, this embossing applied to the absorbent core 8 deforms the surface of the absorbent sheet 9. This makes the projection E projecting from the surface of the sheet 9 a uniform standard. Each of these protrusions E is substantially triangular and one of the sides, R, has a gentle inclined protrusion and the opposite side P has a more steeply inclined protrusion that forms a wall substantially perpendicular to the surface of the sheet 9.

Embossing of the kind described above only results in the appearance of a certain number of voids H on the surface S of the absorbent core 8 and thus ensures that the menstrual fluid is suitably dispersed even with the use of "wet integrated" type paper to make the core 8. Not maximum absorption rate.

The void H described above occurs at the point where the base P of the wall meets the surface of the sheet 9, because in this area the surface pressure of the sheet 9 paper rises causing its fibers to collapse and the substrate torn slightly. This is because the voids appear.

The presence of the strongly absorbing granules 10 contained within the absorbent core 8 contributes to the formation of the voids, since the granules wear the absorbent sheet 9 and create voids on the paper.

Preferably, the absorbent core 8 is embossed so that the wall P is positioned longitudinally with respect to the longitudinal axis of the physiological absorbent article 1. This location of the wall P causes the menstrual fluid to spread out more longitudinally along the absorbent core 8 and is discharged by the super absorbent material 10 through the voids.

The presence of the super absorbent material 10 at the edge of the pores contributes to the best absorption of the menstrual fluid because the direct contact of this substrate 10 absorbs the fluid more quickly.

In a preferred embodiment, the distribution of the protrusions on the surface of the absorbent core 8 is as follows: each area cm ² has about 8 to 15 protrusions at its upper surface and the same amount of protrusions on its lower surface. Most preferably, each area cm ² has 12 protrusions on the upper surface and 12 protrusions on the lower surface of the absorbent core 8.

In a preferred embodiment, the distribution of pores is about 2 to 15 pores per cm ² on the upper and lower surfaces of the core 8. Most preferably, the distribution of voids is about 6 voids per cm ² on the upper and lower surfaces of the core 8.

Further advantages are achieved by using the manufacturing method described above and a fairly inexpensive substrate for producing the absorbent material 1.

By drilling the absorbent sheet 9 of the absorbent core 8 as described above, the super absorbent material 10 is partially exposed so that the generated liquid reaches the absorbent core 8 and is directly absorbed by the super absorbent material 10. And the upper permeable layer 2 and the transfer layer 7 dry rapidly to provide greater comfort to the user of the physiological absorbent product 1.

Perforating the absorbent core 8 improves the absorption and dispersion of the liquid, which reduces the likelihood of leakage of the product 1 and improves the flexibility of the "wet accumulation" paper, since the perforations are used to align the oriented fibers of the substrates mentioned above. For destruction.

In addition, the perforation destroys the impermeability observed on the surface of the "wet accumulation" paper to improve the liquid absorption of the absorbent core 8.

A further advantage of the present invention is that the embossing associated with the perforations is slightly thicker in comparison to the physiological absorbent products of the prior art, so that the absorbent core 8 and thus the physiological absorbent products 1 give greater stability to the user. Is that.

While certain aspects of the invention have been described and described, those skilled in the art will clearly appreciate that various other changes and modifications can be made without departing from the spirit and scope of the invention. In addition, all changes and modifications within the scope of the invention are intended to be protected in the appended claims.

The physiological absorbent core of the present invention can be manufactured economically by using an inexpensive wet integrated paper, and also by the embossing and perforating the absorbent core of the present invention, the physiological absorbent which is given excellent absorption power and great comfort and relief to the user. An absorbent product is provided.

Claims (16)

Liquid permeable top layer, Liquid impermeable underlayer, Transport layer and A physiological absorbent article comprising an absorbent core having a top and a bottom, The core further comprises an absorbent sheet and a super absorbent material attached to the inner surface of the sheet, the sheet consisting essentially of wet laid paper and facing two longitudinal faces (each longitudinal) Cotton is folded over the inner surface). The absorbent article of claim 1 wherein the absorbent core is embossed and perforated. 3. The absorbent core of claim 2, wherein the absorbent core comprises a plurality of protrusions (the protrusions are essentially triangular in cross section) on its surface, one side of which has a slanted protrusion, the opposite side of which has a steep slope, and a steep protrusion. An absorbent article in which the face having is positioned essentially parallel to the longitudinal direction of the absorbent core. The absorbent article of claim 3 wherein the absorbent core comprises 8 to 15 protrusions per cm ^{2 in} both the top and bottom. The absorbent article of claim 2 wherein the absorbent core comprises 2 to 15 perforations per cm ^{2 in} both the top and bottom. The absorbent article of claim 1 wherein the absorbent under load value of the superabsorbent is at least about 24 ml of saline per gram of superabsorbent. The absorbent article of claim 1 wherein the porosity of the super absorbent material is at least about 0.15. The absorbent article of claim 1 wherein the performance under Pressure capacity value of the super absorbent material is at least about 23 g / g at a limit pressure of 0.7 psi. The absorbent article of claim 1 wherein the saline flow conductivity value of the super absorbent material is at least about 30 × 10 ⁻⁷ cm ³ seconds / g. As an absorbent core for use in physiological products, The core has an upper and a lower absorbent sheet (the sheet comprising two longitudinal faces, essentially consisting of a wet aggregate paper, each longitudinal face folded over an inner surface) and the inner surface of the sheet An absorbent core comprising a super absorbent material attached to the. 11. The absorbent core of claim 10 being embossed and perforated. 12. A surface according to claim 11, comprising a plurality of protrusions (the protrusions are essentially triangular in cross section) on one surface, one side having a slanted protrusion and the opposite side having a steep slope and a slope having a steep protrusion. An absorbent core positioned essentially parallel to the longitudinal direction of the absorbent core. The absorbent core of claim 12 comprising 8 to 15 protrusions per cm ^{2 in} both top and bottom. 12. The absorbent core of claim 11 comprising from 2 to 15 perforations per cm ^{2 in} both top and bottom. Spraying the adhesive onto the wet integrated paper sheet, Applying a super absorbent material onto the adhesive material, Folding the paper sheet to form an absorbent core, and Embossing and perforating the absorbent core, the method of producing an absorbent core for use in a physiological absorbent article. 16. The embossing step of claim 15, wherein the embossing step comprises a surface having a slanted protrusion on one side (the protrusion is essentially triangular in cross section), an opposite side having a steep slope protrusion, and a face having a steep slope protrusion in the longitudinal direction of the absorbent core. And creating a plurality of protrusions located essentially parallel on the surface of the absorbent core.