JPH0410339B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is a disposable diaper in which a polymer with a slow absorption rate and strong gel strength is disposed on the surface nonwoven fabric side so that the user can use it until the polymer is saturated. This invention relates to a disposable diaper in which a polymer with a fast absorption rate and low gel strength is disposed on the waterproof polyethylene sheet side of the back surface.

[Prior art] The absorbers currently used in disposable diapers include a laminated type of absorbent paper, a cotton-like pulp type made by crushing pulp into layers, and a type of polymer powder sprinkled between the cotton-like pulp. Recently, due to the improvement in the quality of polymer powder and the regular cost, many diapers using polymer powder are on the market. Laminated absorbent paper allows urine to spread, but it has an absorbing capacity of only 7 to 8 times its own weight and quickly becomes saturated. Products that use only cotton-like pulp have an absorption capacity of about 10 times their own weight, but because they do not spread, the area that absorbs urine becomes sticky. In addition, when one type of polymer is sprinkled on cotton-like pulp, the polymer powder itself has a urine absorption capacity of about 50 times its own weight, so a considerable amount of urine will be absorbed before it becomes saturated. However, due to the slow absorption rate of urine, urine did not diffuse sufficiently.

In JP-A No. 62-45702, superabsorbent polymeric substances are provided in layers on both sides of a water-absorbing sheet, and a layer with a second water-absorbing capacity is provided on the first water-absorbing layer side of the water-absorbing sheet.
A super-absorbent polymer material having a water absorption capacity smaller than that of the water-absorbing layer side is provided on the second water-absorbing layer side of the water-absorbing sheet. A device in which a highly water-absorbing polymeric material with high capacity is provided is disclosed. In other words, the publication states that the water absorbency of the first water-absorbing polymer material in the upper layer is higher than that of the second water-absorbing material in the lower layer.
The water absorption is made smaller than that of the super absorbent polymer material on the water absorption layer side. Therefore, urine is not sufficiently diffused in the highly water-absorbing polymer material on the first water-absorbing layer side, but is absorbed by the highly water-absorbing polymer material on the second water-absorbing layer side, which has absorption capacity. Lacks diffusion ability. Therefore, there is a drawback that urine oozes out from the first water-absorbing layer side of the water-absorbing sheet and becomes sticky to the human body.

[Problem to be solved by the invention] When a diaper is worn, urine does not cover the entire diaper, but is urinated only in one place, and due to the characteristics of the polymer, only that part retains moisture, and after it becomes saturated, it is released. It spreads to the surrounding area, but the area where it was first absorbed is saturated, so if you hold it down, it will leak back and become sticky on the skin. It is extremely unpleasant for diaper users or those who use the diaper to feel sticky when using it, so it is desirable to always wear it dry so that there is no feeling of use.

[Means for Solving the Problems] In order to solve the problem of stickiness, the present invention uses polymer powders with different gel strengths and arranges a polymer with strong gel strength on the surface nonwoven fabric side with an intermediate nonwoven fabric in between.
A polymer with low gel strength is placed and sprayed on the back waterproofing polyethylene sheet side. That is, as shown in FIG. 2, a first flocculent pulp layer 7 is first formed, a polymer powder 6 having a fast absorption rate and low gel strength is sprinkled thereon as a first polymer layer, an intermediate nonwoven fabric 5 is placed thereon, and a second Place the cotton pulp layer 4 and the second
After scattering a polymer powder with a slow absorption rate and strong gel strength as the polymer layer 3, the third flocculent pulp layer 2 is layered on top of it to form an absorbent body, and under the first flocculent pulp layer 7, a waterproof part is formed. A transparent polyethylene sheet 8 is spread, and a nonwoven fabric 1 made of polyester, polypropylene, rayon, etc. is placed on top of the third cotton-like pulp layer 2 as a top sheet to form gears 9 on both sides, and both ends are glued with hot melt adhesive. It was made into a disposable diaper with tape attached.

[Function] Urine absorbed from the surface nonwoven fabric 1 passes through the third flocculent pulp layer 2, is diffused in the second polymer layer 3 with strong gel strength, and is then transferred to the second flocculent pulp layer 4 by the user's wearing pressure. It is slowly absorbed, and the intermediate nonwoven fabric 5
The polymer is diffused back and forth and goes to the first polymer layer 6. The polymer powder of the first polymer layer 6 has a high absorption rate and low gel strength, so it quickly takes in water in urine in a diffused state.
It traps even the moisture attached to it. When urine reaches the first polymer layer 6 one after another and reaches a saturated state, the urine goes up through the intermediate nonwoven fabric 5 to the second cotton-like pulp layer 4 in a diffused state due to the pressure of the wearer. The second polymer layer 3 contains a second polymer powder that has a slow absorption rate but strong gel strength, so it catches the urine that slowly rises and does not carry it up to the third cotton-like pulp layer 2, so the nonwoven fabric 1 on the surface It's smooth and not sticky.

Example 1 An example of the present invention in which only an absorbent body is taken out will be described below.

200g/ ^m2 flocculent pulp (first flocculent pulp 4)
Gel strength 4-5 dyne/cm, absorption rate approx. 3
Wet back properties (reverse rebound properties) of an absorbent material made by uniformly dispersing 90 g/m ² of polymer (second polymer layer 3) and layering 200 g/m ² of cotton pulp (third cotton pulp 2). investigate.

Example 2 The polymer powder of Example 1 had a gel strength of 5 to 6 dyne/
cm, absorption rate of 4 to 5 seconds to examine wet back properties (first polymer layer 6).

Example 3 200 g/m ² flocculent pulp (first flocculent pulp 7)
45 g/m ² of the polymer powder used in Example 1 was sprinkled on top (first polymer layer 6), a 15 g/m ² dry nonwoven fabric with fluff (intermediate nonwoven fabric 5) was placed as an intermediate nonwoven fabric, and 200 g/m 2 After stacking the flocculent pulp of ^{No. 2} (first flocculent pulp 7) and uniformly scattering the polymer powder used in Example 2 (first polymer layer 6) on top of it, the same flocculent pulp of 200 g/m ² The pulp (second flocculent pulp 4) is placed on the absorbent body and wet back properties are examined.

Wetback property (reverse return property) test method: Pour 100 c.c. of 1% saline solution onto the center of the specimen, leave it for 3 minutes, then place 5 filter papers weighed on it.7
After placing a kg weight on it for 1 minute, measure the weight of the saline solution transferred to 5 pieces of filter paper.

The smaller the number, the less likely it will be reversed.

Results Example 1 15.7g Example 2 13.4g Example 3 2.5g As shown above, two types of polymer powder (layer) with high gel strength and polymer powder (layer) with low gel strength are used for the same weight of polymer powder. By using a polymer, wet back properties can be improved.

[Brief explanation of drawings]

Figure 1 is a perspective view of the diaper according to the present invention, Figure 2 is a perspective view of the diaper according to the present invention;
The figure is a cross-sectional view of the diaper according to the present invention, 1 is a surface nonwoven fabric, 2 is a second cotton-like pulp, 3 is a second polymer layer with strong gel strength, 4 is a second cotton-like pulp, 5 is an intermediate nonwoven fabric, and 6 is a gel first polymer layer with low strength; 7
8 is a waterproof polyethylene sheet, and 9 is a gear part.

Claims (1)

[Claims] 1 A first flocculent pulp layer 7, a first polymer layer 6 made of a polymer powder having a fast absorption rate and low gel strength and sprinkled on the first flocculent pulp layer 7; an intermediate nonwoven fabric 5 placed on top, and a second cotton-like pulp layer 4 stacked on the intermediate nonwoven fabric 5
A second polymer layer 3 made of a polymer powder with a slow absorption rate and strong gel strength is sprinkled on the second flocculent pulp layer 4, and a second polymer layer 3 is made of a polymer powder with a slow absorption rate and strong gel strength, and a second polymer layer 3 is layered on the second polymer layer 3 as an absorbent material. 3 cotton-like pulp layer 2, a waterproof polyethylene sheet 8 disposed on the surface of the first cotton-like pulp layer 7, a surface nonwoven fabric 1 disposed on the surface of the third cotton-like pulp layer 2, and a waterproof polyethylene sheet 8 and the geared parts 9 on both sides of the surface nonwoven fabric 1,
A disposable diaper characterized by having both ends secured with hot melt adhesive.