JPS58112539A - Sanitary napkin with absorption aid - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to sanitary products, and particularly to a menstrual napkin with excellent fluid transfer properties.

Two problems associated with sanitary products such as diapers, chastity pads, and sanitary napkins are the fluid movement of the absorbent medium packed into such sanitary products and the ease of wear.

It is desirable to move the fluid as quickly as possible to the final holding position K away from the sanitary article surface closest to the outlet. Rapid transfer is desirable not only from the standpoint of drying the wearer's body, but also to keep the appearance of the used sanitary product as unsightly as possible.

Hitherto, such sanitary products have consisted primarily, or as an absorbent component, of inexpensive, relatively bulky cellulosic products such as fluffed wood pulp cotton or -. Because it is inexpensive and has a good appearance when dry, it is used as a fluff-like material (hereinafter referred to as fluff).
luff) or similar materials are preferred.

Although fluff has an attractive appearance, there are drawbacks to its use as an absorbent material in sanitary products.

When fluff gets wet, it is crushed from the inside and becomes very dense and loses its elasticity. In addition, fluff cannot be said to be highly efficient in terms of absorption amount per volume.

However, as a result of comparing the costs of fluff and other absorbent materials, fluff and similar hilulose-derived products have come to be used as the main absorbent material in most sanitary products.

In areas other than sanitary products, various attempts have been made to increase the absorbent capacity of fluff, nokulp gates, and related products. US Patent No. 79! ;'Ig4t! No. i and No. 073. No. 10 describes a method for forming a plurality of additional webs or layers with absorbent paper properties. The above web is made from Takashinya's alpha cellulose wire cone, and is flattened.
), napping (napplng), curling (crumple ing), and other operations. The above-mentioned fluke formation (fluHlng) operation causes the fibers to spread and be distributed on both sides of the web.

According to the technique described in the prior patent mentioned above, an absorbent packaging material is made from a stack of the above-mentioned sheets. This packaging exhibits an omnidirectional absorption function, with greater longitudinal moisture transfer across the web surface than infiltration in the two directions, i.e., in the stacking direction. Attempts have been made to provide longitudinal slits to compensate for this lack of moisture transmission in two directions. Two-way transmission is difficult because the bulky ## fine hairs on both sides of the web form a series of layers in which a high-density sheet core and a bulky, fluffy surface alternate when the web is stacked. This is the result of forming a structure. Since the entrapment (w + cbtng) occurs only from the region with large holes to the region with small holes, the bulky fluff layer created by two adjacent raised fuzzy surfaces acts as a barrier to two-way transmission. Work as.

Other attempts to improve the absorption capacity or transmission of absorption of Gulde sheets have been made throughout the art. An example of this type of attempt is US Patent #! 3. ,
! In this prior art, pulp sheets are stacked loosely, dried to remove at least 30% moisture with minimal pressure, and then bent. Manipulation or breaking of interlocking bonds or other means creates an open soft surface layer. The sheet thus obtained is a soft and pliable cellulose 1# mackerel body having multiple layers with different absorption properties.

Another example of a web made of cellulosic material is disclosed in US Pat. No. 19G&297, which discloses a method for producing a dry web. However, none of the above-mentioned prior patent specifications discloses the juxtaposition of the characteristics of sanitary products by combining fluff or similar known absorbent materials with other materials. None of the materials described in this article can function solely as absorbent materials for sanitary products. Particularly when replenishing fluids or menstrual fluids are to be absorbed into sanitary products, the prior art uses Full is not fit for purpose.

In the case of sanitary napkins, in particular, the concept of using multicomponent tissue absorption systems is known.

In this technical field, there is an extremely large amount of literature regarding sanitary napkins and tampons that combine the prior art cellulose-based materials with intermediate materials that are small in bulk and have high absorbency per unit volume. Materials with a quality called super absorbent are particularly preferred because of their high adsorption power, which allows a relatively large amount of fluid to be adsorbed onto an extremely small volume of absorbent material. Theoretically, a composite napkin or tampon combining absorbent materials such as those described above with prior art absorbent materials would be a sanitary product with low bulk and therefore good wearability without adversely affecting absorbency. It can be said that it provides the following.

In the case of sanitary napkins or tampons, it is clear that superabsorbents pose more serious problems than they solve. However, superabsorbent materials are
The maximum theoretical absorption capacity cannot be achieved due to a phenomenon called gel blocking. gel·
The blocking is apparently due to the fact that the absorption of the water-soluble portion of the waste is extremely rapid, while at the same time other components of the menstrual fluid, such as cytoplasmic debris and myxoid particles, form a coating on the superabsorbent surface. It happens by doing. The coating layer immediately becomes a hindrance to further adsorption of fluid, substantially inhibiting the usefulness of this type of absorbent material. The problem of gel blocking has already been recognized in the art, and attempts have been made to minimize this deleterious effect by incorporating other interstitial components into the superabsorbent material. However, no attempt has been completely successful.

US% FF No. '70! ;z06 / issue Q [In the book, O,
OS~0.7! A sanitary napkin is described having a fluff component densified to have a density of tμ. According to this prior patent specification, the densified layer provides adequate absorbency with reduced size. Although a small absorbent material may or may not be additionally inserted into the sanitary napkins manufactured according to this prior patent, the compressed absorbent pulp is designed to be the main absorbent component that holds the volume. This is the main feature.

However, this prior patent's one-shot problem-solving method has its own drawbacks. The layer of absorbent material is compressed and densified. Due to high density, the capillary becomes smaller, and because the size of the capillary becomes smaller, the capillary wicking action through the wrapping paper part of the sanitary napkin increases, making the capillary more likely to become clogged. It is no longer able to flow downward through the layer and quickly migrates onto the surface of the compressed layer. Eventually, the above sanitary napkins with a compressed pulp layer become partially stained due to surface migration of fluids. If the bulk of the napkin is reduced to make it more comfortable to wear, the chances of the sides becoming soiled will also increase. In addition, in the case of the indigo drying compressed body used for forming the densified layer of the above-mentioned prior patent, bonding occurs within the layer itself. Repeated handling and storage during the manufacturing process also tend to reduce the miniaturization effect, and the napkins tend to return to their original bulk later.

In accordance with the present invention, a sanitary napkin is produced having a conventional bulky first absorbent layer and an absorbent insert consisting of densified fluff. The densified layer is truncated in the shape of a frustum and does not reach the edge of the upper absorbent layer. Due to densification, the capillary tube becomes smaller, which quickly sucks fluid through the bulky absorbent layer of the conventional method, and due to densification,
The fluid spreads along the upper surface of the second compressible absorbent layer, resulting in a better distribution of fluid within the napkin and away from the wearer's body.

The sanitary napkin shown in FIG. 1 has a fluid permeable cover 16 that spans and wraps around the absorbent layer 10. In the illustrated embodiment:
The absorbent layer 10 is folded under the compressed fluff absorbent insert layer 13 to form a bottom absorbent layer 12 . These absorbent layers are completely surrounded by fluid permeable latches f (surrounding @ 轡) 16, as shown by dashed lines 11.
The surface in contact with the fluid-impermeable baffle 14 is sealed by adhesive or welding. As shown by band 15, the ends of the sanitary napkin are sealed by welding the thermoplastic weldable wrap 14 itself.

The embodiment shown in FIG. 1 is preferred for reasons that will become clear from the following considerations. The teachings of the present invention do not necessarily apply to the seventh
As shown in the figure, it is not essential to fold the upper absorbent layer 1° so as to cover the absorbent insert, but the upper absorbent layer is integrally formed of fluff and thermoplastic micro #I#. This is a preferred structure when the mixture is a mixture. This type of adsorbent layer is described in U.S. Pat. ．． 1 in the specification of No. 321I
It consists of an air-formed thermoplastic polymer fiber matrix having a structure in which a large number of independent wood loop fibers are dispersed in a thermoplastic matrix having an average diameter of less than /θ dens.

The upper absorbent layer is first formed using secondary airflow, and then meltblown (meltblown) @ primary air in which small fibers are floating is fused with a mixed air flow containing wood pulp mackerel fibers. Therefore, make it. Both insulations coalesce under turbulent flow conditions and fall into their respective positions in a unified air stream along the forming surface.

A sanitary napkin according to the invention having an integrally molded layer surrounding a densified absorbent wood flap insert results in a highly resilient napkin in both wet and dry conditions. The sanitary napkin according to the preferred embodiment of the present invention uses a compressed absorbent insert, so that the diffusion rate of the discharged fluid increases when the blade diameter increases, so that it has an appropriate adsorption force. An absorbent insert having a relatively modest fluid adsorption capacity increases the utilization of the remaining absorbent material portion due to horizontal suction due to fluff compression and densification.

Of course, fluff or similar materials known in the art could be used as the top layer, but for the purpose of the present invention, the area of the absorbent insert and the top absorbent layer are It is an essential requirement that the head of the material insert be frustum-shaped. whether the upper layer is folded over the absorbent insert;
The above requirements must be met.

The densified insert according to the present invention is characterized in that the densification is at least θ,
7 (It is compressed to be HIJ.The minimum compression amount is -F
Determined by the density of the sublayers, the density of the insert must be greater than the density for fluid to reach the absorbent insert surface through the upper layer and be adequately adsorbed. Generally speaking, the density of the insert is θ, /fAr−~0.4t t7t
Keep it within the range of r-. Because it would be extremely difficult to do anything other than using the temporary bonding force caused by air-based sedimentation, the air-based fluff layer is increased by spraying water in the form of a spray and with the help of a thermal calendaring roll. Densification is a highly desirable method. It has been found that within the range of the meter mentioned above, it is preferable to set the density after initial water injection densification to θ,/g fAI-1g-. (Although there is some rebound of the densified web after an extended period of time, this rebound is very slight in nature.) The densified layer is of uniform density throughout;
U.S. Patent #Co, 90&kAg and No. 3θ/'730
It is necessary to avoid the formation of so-called surface skin layers, as described in No. 11.

Since the presence of this type of skin substantially suppresses fluid adsorption, it must have sufficient fluid suction and fluid retention to the extent that the napkin is torn as it falls into the densified fluff layer. .

Providing sufficient wall thickness to incubate all layers of fluff facilitates uniform densification during prior art air deposited fluff web production. At least 7
Use a hot roll of books to compact the wet fluff surface. The degree of densification thereby obtained is a function of roll temperature, processing speed and roll pressure. If#l densification layer close to the preferred density has a processing speed of 3. θ3 rrv
% (/0 time), processing temperature g2. −℃＜igo
Hot rolling drives the moisture inside the fluff and does not thin the skin formation on the moisture addition side.The uniform densification obtained is due to the permanent setting of the cellulosic fibers. It is thought that this is the result of either fiber bonding or both.By increasing the temperature of the backing roll depending on the thickness of the initial fluff layer,
It is also desirable to prevent the formation of a densified layer on the bottom of the web. It is possible to achieve excellent absorbency, low bulk, and efficient use of absorbent material. To achieve the objectives of the present invention, the width of the absorbent layer on each side is at least 0.0 mm wider than the gadth of the upper absorbent layer. ．． Preferably, it is smaller than 2tys. More preferably, the width difference is at least 0
．． Make it kan. Although not necessarily an essential requirement, it is desirable that the length of the absorbent insert be less than or equal to the total length of the upper absorbent layer.

[Brief explanation of the drawing]

Although shown in FIG. 1, FIG. 7 is a partially cutaway perspective view of the sanitary napkin according to the present invention. 10...Absorbent layer, 12...Bottom absorbent layer, 13...Fluff absorbent material insertion layer, 1
4...Fluid-impermeable baffle, 15...
...Band, 16...Fluid permeable cover (
fluid permeable wrap) FIG, mouth

Claims (5)

[Claims] (1) (Hata) fluid-impermeable baffle; (b) fluid-impermeable baffle;
an absorbent layer; (e) a second uniformly densified absorbent fluff layer having a controlled absorbent capacity and having a K11t between the first absorbent layer and the baffle; 0. than the density of the first absorbent layer. A sanitary napkin comprising an absorbent fluff layer having a density of /174b or more and having a width wider than the width of the first absorbent layer. (2) Claim (1) K, characterized in that the first absorbent layer is a fluffy layer.
T! Soft sanitary napkins. (3) Claim (1) characterized in that the first absorbent layer is made of a mixture of cellulose fibers and thermoplastic microfibers integrally formed by an air flow method.
Sanitary napkins as described in section. (4) 45F indicates that there are two or more absorbent layers.
The sanitary napkin according to claim (3), which is defined as im. (5) The first absorbent layer is folded in the transverse direction, wears down the second absorbent layer, and covers at least a portion of the side surface of the second absorbent layer facing the baffle. Claims (Paragraph 11, Section (2)
Item #(31) or item (4).