JPS599619Y2 - water absorption sheet - Google Patents

Description

[Detailed description of the invention] This invention relates to a water-absorbing sheet using a super-absorbent polymer, which is used for the water-absorbing layer of sanitary napkins and disposable diapers. Regarding the water-absorbing sheet held in place.

Although the water-absorbing sheet of the present invention can be used as an absorbent material for body fluids such as sanitary napkins and disposable diapers,
For convenience of explanation, a sanitary napkin will be explained below as an example.

In order to improve the performance of sanitary napkins, highly absorbent polymers known as hydrogels have recently been used in the absorbent layer.

Super absorbent polymers can absorb 20 to 400 times their own weight over time, and have the ability to retain water even under pressure, so various application techniques are being studied.

JP-A No. 52-3113, Japanese Patent Publication No. 54-4666
In addition, US Pat. No. 3,661,154 and the like disclose a technique in which a superabsorbent polymer is mixed with pulp.

This method has concerns about the positional stability of the superabsorbent polymer, which may move during use of the sanitary napkin.

In addition, Japanese Patent Publication No. 53-38645 describes a technique for applying a superabsorbent polymer to thin water-absorbing paper;
No. 2-130739 discloses a technology for a water-absorbing sheet in which a highly water-absorbing polymer is sandwiched between two sheets of thin water-absorbing paper in the form of a sandwich.

Using this method, three-dimensional diffusion of the superabsorbent polymer is prevented, and concerns about positional stability are resolved by fixing two thin sheets of absorbent paper, but the degree of adhesion of the thin sheets of absorbent paper depends on the paper quality. different.

Furthermore, in order to effectively use a superabsorbent polymer, it is necessary that menstrual blood spreads out in a plane before coming into contact with the superabsorbent polymer.

This is a matter that depends more on the properties of the thin absorbent paper holding the superabsorbent polymer in the absorbent sheet.

The present invention was perfected by focusing on the fact that the crepe shape of thin water-absorbing paper contributes to the performance of the water-absorbing sheet.

The structure of the water-absorbing sheet of the present invention is shown in FIG.

That is, the superabsorbent polymer 3 is sandwiched between two sheets of thin water absorbent paper 1 and 2 in a sandwich-like manner.

Although the thin water-absorbing paper 1 has a higher crepe ratio, it is better to have a crepe ratio of 50% or more, although it varies depending on the raw material pulp and additives.

Here, the crepe ratio indicates the ratio of the area of paper with crepe applied, based on the area without crepe.

The crepe rate of ordinary thin water-absorbing paper is often 30 to 60%.

The basis weight of the thin water absorbent paper is 20 to 30 g/m2, and the thickness when 10 sheets are stacked without load is 2 to 5 mm.

To describe these in words, they are very crepe-like and have a thick, thin, water-absorbing paper feel.

As shown in FIG. 2, the thin water-absorbent papers 1 and 2 can have points 4 attached to each other at desired locations.

This is to prevent the superabsorbent polymer from moving.

Any superabsorbent polymer called hydrogel can be used for the water absorbent sheet of the present invention.

Typical examples include crosslinked ethylene oxide polymers, crosslinked acrylic acid metal salt polymers, crosslinked carboxymethyl cellulose metal salts, starch polyacrylic acid metal salt block copolymers, and copolymers of acrylic acid metal salts and vinyl alcohol copolymers or block copolymers. There are mergers, etc.

The water-absorbing sheet of the present invention is structured as described above, so when menstrual blood reaches the thin water-absorbing paper 1, it spreads flat on the thin water-absorbing paper 1 because the thin water-absorbing paper feels thick. Menstrual blood comes into contact with the super absorbent polymer, allowing the super absorbent polymer to be used effectively.

The thin water-absorbent paper 1 may be used so as to be positioned on the skin side,
It may also be used on the opposite side of the skin.

In this case, menstrual blood passes through one layer of the superabsorbent polymer and spreads flatly under the superabsorbent polymer.

Of course, the same paper as the thin water-absorbing paper 1 can also be used for the thin water-absorbing paper 2.

In addition, since the thin water-absorbing paper 1 feels rather thick, when attaching the two thin water-absorbing papers as shown in Fig. 2, it is easy to attach them just by applying embossing with light pressure, and the basis weight is small. Since it is 20 to 30 gr, a water-absorbing sheet with appropriate strength and flexibility can be produced.

The following is an example of an experiment to help understand the present invention.

As mentioned above, the present invention provides a water absorbent sheet with excellent performance.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the water absorbing sheet according to the present invention;
The figure is a sectional view of another embodiment of the water absorbent sheet according to the present invention. 1...Top paper, 2...Bottom paper, 3...
...Super absorbent polymer 4... Attachment point.

Claims (1)

[Claims for Utility Model Registration] A water-absorbing sheet in which a superabsorbent polymer is arranged between two sheets of thin water-absorbing paper, in which at least one of the thin sheets of water-absorbing paper has the following characteristics. (b) Crepe rate is 50% or more. (b) The weight per square meter is 20 to 30 grams. (c) The thickness when stacking 10 sheets without any load is 2 to 6 mm.