JPS642061B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water-absorbing material using a water-insoluble water-absorbing resin (hereinafter simply referred to as water-absorbing resin), particularly one having a high water-absorbing property of absorbing water at least 50 times its own weight. Conventionally, water-absorbing resin powders or granules have been used directly or together with carriers to make sanitary napkins,
Many water-absorbing materials have been known that can be sprayed or mixed with disposable diapers, paper towels, sealed wet towels, and other soil cultivating soil to increase their water-absorbing effects. However, in applications such as sanitary napkins and disposable diapers, the above-mentioned water-absorbing resin selectively binds to salts contained in living organisms, especially common salts, causing a decrease in water-absorbing performance; The inventors of the present invention have found that the reduction is 1/2 to 1/10 compared to when it is not used. This invention is intended to improve the drawbacks of the known water-absorbing materials as described above, and is to obtain a water-absorbing material whose water absorption rate does not decrease significantly even when water contains hypochlorite salts. sanitary napkin,
It is intended for use in packaging paper diapers, paper towels, and the roots of seedlings or flower seedlings. This invention is a water-absorbing material characterized in that a combination of a powder or granular water-absorbing resin and an ion-exchange resin is wrapped in a flat water-permeable fibrous sheet. The water-absorbing resin used in this invention includes at least one of the following: a saponified starch-polyacrylic acid copolymer, a self-crosslinking polyacrylate, a saponified starch-polymer acrylonitrile copolymer, and PVA. Uses resins that absorb more than 50 times their own weight in water, such as saponified vinyl ester/ethylenically unsaturated carboxylic acids, ethylene terpolymer copolymers, and saponified vinyl ester/methacrylate copolymers. In the present invention, there is no particular limitation on the material as long as it is a water-absorbing resin. Even if the water-absorbing resin used in this invention is uniformly dispersed in a suitable granular or powdery carrier in advance, the invention is the same. In addition, the ion exchange resin used in this invention may be a commercially available one, such as a strong basic anion exchange resin,
The invention is the same regardless of whether one of the strongly acidic cation exchange resins or a mixture of the two is used, preferably at a mixing ratio (wet) of 2:1 to 3:1. . As the water-permeable fiber sheet, at least one of paper, pulp, nonwoven fabrics made of cotton, linen, synthetic fibers, fine woven fabrics, knitted fabrics made of these fibers, etc. is used. Next, typical embodiments of the present invention will be described based on the drawings. The ones shown in FIGS. 1 to 5 are examples of sanitary napkins A, and the one shown in FIG. The body 10 is flatly wrapped with a nonwoven fabric 11, and the peripheries 12 of the nonwoven fabric 11 on the front and back sides are adhered. In the case shown in FIG. 3, the water absorbent resin 13 and the ion exchange resin 14 are not mixed, and the water permeable sheet 15
For example, the nonwoven fabric 11 or tissue paper may be used to divide the layer into layers, and the entire nonwoven fabric 1 may be used as a layer.
1 is included in the same manner as in FIG. In the case shown in FIG. 4, a paper towel 16 is placed between the layers of water-absorbing resin 13 and ion-exchange resin 14 and on both outer sides thereof, and the whole is covered with non-woven fabric 11 in the same manner as shown in FIG. In the system shown in FIG. 5, a strongly basic anion exchange resin 18, a strongly acidic cation exchange resin 19, and a water absorbent resin 14 are each wrapped in a sheet shape with a sheet 17 made of pulp, and these are sequentially stacked one on top of the other. resin 1
4 side is the innermost side, this outer side and all the peripheral parts of the sheet-like material are covered with a water-impermeable membrane 20, and the top layer ion exchange resin-covered sheet surface is exposed to the outside or covered with a nonwoven fabric 11. This is what I did. The sheet shown in Figure 6 is sheet B used for packing the roots of seedlings, and its overall structure is similar to those in Figures 1 to 4, but the overall planar shape needs to be larger. A reinforcing fabric sheet 21 is sewn or glued to one or both sides depending on the case. Although there is no particular limitation on the size of the sheet B, for example, it may be 50 to 60 cm wide, 90 cm wide, 180 cm wide, etc., and it is used as a long sheet and cut as necessary. Although not shown in the drawings, the present invention would be the same even if the tape was made into a tape having a width of 5 cm to 10 cm and wrapped around a tree trunk or the like. What is shown in FIG. 7 is a perspective view of the paper diaper C, and the internal structure is the same as that in FIGS. 2 to 5. In the water-absorbing material of the present invention configured as described above, even if urine, blood, sweat, body fluids, etc. containing salts come into contact with the water-absorbing material, the salts in these solutions are selectively absorbed by the ion exchange resin. Because of the preferential binding, the concentration of salt absorbed into the water-absorbing resin is reduced, and the rate of decrease in the water-absorbing capacity of the water-absorbing resin is significantly improved, approximately 1.5 to 2.5 times that when no ion-exchange resin is used. The water absorption effect can be improved. In addition, when these sheets B are pre-impregnated with water and used for packaging the roots of plants or for preventing drying of flower beds, even if salts are contained in well water, these salts are selectively removed as described above. In order to bind preferentially to the ion-exchange resin, the water-absorbing resin contains sufficient water, and by using the sheet of this invention, the roots can be prevented from drying out, and when transporting or transporting plants, etc. There is no need to replenish water frequently. If the ion exchange resin and the water absorbent resin are formed into layers and used so that the aqueous solution comes into contact with the ion exchange resin 13 first, the above-mentioned effect will be even more remarkable, and the initial water content will be improved. Therefore, it is suitable for cases such as disposable diapers. As shown in FIG. 5, if one side of the outside and the surrounding area is covered with a water-impermeable membrane 20, the aqueous solution that has once absorbed water will leak out even if it is pushed out by the external pressure applied to this water-absorbing material. There is no fear. As shown in Figure 6, materials that are integrated with woven fabric, or those that are covered on the outside with woven fabric or knitted fabric such as stockinette, are less likely to tear, and those that are knitted are less susceptible to deformation. It is easy to apply and follows the texture or the shape of plant roots well. When the ion exchange resin is a mixture of a strongly basic anion exchange resin and a strongly acidic cation exchange resin, when the liquid that has absorbed water oozes out again, the pH of the solution becomes almost neutral. There is no risk of skin irritation as it ages, and there is no need to adjust the pH when discarding it. This effect will now be demonstrated using an experimental example. Experimental example Material a; Water-absorbing resin (see number 14 in the figure) = Self-crosslinking polyacrylate (((Product name: Aqua Keep 4S powder, manufactured by Steel Chemical Co., Ltd.)) b-1; Strong basic anion Exchange resin ( ( ( ( ( ( Trade name Amberlite ) Regenerated ion exchange resin with IRA - 400 as OH ) ) ) ) ) b - 2 ; Strongly acidic cation exchange resin ( ( ( ( ( Trade name Amberlite ) Regenerated ion exchange resin made from H-type IR-120 ) ) ) ) ) c; Non-woven fabric A mixture of polyester and cellulose fibers, a of 0.2g, and b-1 and b-2 of 20g and 8g in wet weight. , Mix this uniformly and spread it over two pieces of 10cm x 15cm non-woven fabric.
As shown in the figure, Example 1 is inclusive, and b-1
Example 2 is a mixture of and b-2, and a is divided into separate layers with a laminated nonwoven fabric and wrapped in a nonwoven fabric of the same size as in Example 1 as shown in Figure 3. The structure shown in FIG. 4 is referred to as Example 3, and as a control experiment, one in which only a water-absorbing resin was simply wrapped in a nonwoven fabric without using an ion exchange resin was used. Experimental method: 100 ml of 09% NaCl aqueous solution was gradually dropped onto the top surface of the water-absorbing material, left to stand for 1 hour, water was drained, and the weight was measured. The water content of the water absorbent resin was measured by subtracting the dry weight of the water absorbent resin and the water content of the nonwoven fabric (including the water content of the paper towel in Example 3) from the total weight of the entire water absorbent material. The results are shown in the table.

[Table] As can be seen from the results shown in the table above, the ion-exchange resin used was 5% higher than the one not used.
The water absorption effect has been improved by 9 times to 9 times, and if you use the same amount of water absorbent resin as before, you can increase the water absorption effect by 5 to 9 times compared to conventional products, and you can achieve the same effect as conventional products. If available, the amount of water-absorbing resin used may be 1/5 to 1/9. Exactly the same experiments were conducted for water-absorbing resins other than those shown in the above-mentioned experimental examples, and the results showed almost the same trends as shown in the table, so the experimental results will be omitted.

[Brief explanation of the drawing]

The drawings relate to this invention, and FIG. 1 is a perspective view of a sanitary napkin according to the first embodiment, and FIG.
The figure is a vertical sectional view of FIG. 1, and FIGS. 3 to 5 are
Embodiments with different internal structures from those shown in Figures 1 and 2, Figure 6 is a perspective view of a sheet for packing the roots of seedlings using the water-absorbing material, and Figure 7 is a diagram showing the water-absorbing material. It is a perspective view of the diaper used. Symbols in the figure, A... Sanitary napkin, B... Sheet for packing the roots of seedlings, C... Diaper, 10... Mixture of water absorbent resin and ion exchange resin, 11... Nonwoven fabric, 13... Water absorbency Resin, 14... Ion exchange resin, 15... Water permeable sheet, 16... Paper towel, 17... Pulp sheet, 18... Strong basic anion exchange resin, 19... Strong acidic cation exchange resin, 20... Impermeable membrane, 21... Woven fabric sheet.

Claims (1)

[Claims] 1. A water-absorbing material characterized in that a combination of a powder or granular water-insoluble water-absorbing resin and an ion-exchange resin is surrounded by a flat water-permeable fibrous sheet. . 2. The water-absorbing material according to claim 1, characterized in that a water-insoluble water-absorbing resin and an ion exchange resin are uniformly mixed. 3. The water-absorbing agent according to claim 1, characterized in that an ion exchange resin layer and a water-insoluble water-absorbing resin are formed with a water-permeable sheet sandwiched therebetween. 4. The water-insoluble water-absorbing resin is at least one of a saponified starch-polyacrylic acid copolymer, a self-crosslinking polyacrylate, a saponified starch-polyacrylonitrile copolymer, and PVA. Claims 1 and 2,
Or the water-absorbing material described in Section 3. 5. The water-absorbing material according to claim 4, wherein the ion exchange resin is composed of a strongly basic anion exchange resin and a strongly acidic cation exchange resin. 6. Claim No. 6, characterized in that the ion exchange resin is a mixture of a strongly basic anion exchange resin and a strongly acidic cation exchange resin at a wet weight ratio of 2:1 to 3:1. Water-absorbing material described in item 5. 7. The water-absorbing material according to claim 6, wherein the shape that is flatly wrapped in the nonwoven fabric is one of a square, rectangular, oval, tape shape, or sheet shape.